Back in the 1990s, John Self, the general manager of the Victoria line at the time, gave a talk about his vision for its future. From the outset he pulled no punches. It was time, he said, to start thinking about what was going to happen when the line’s trains needed replacing. It was time to start planning for a Tube line fit for the 21st Century. He called his talk ‘The Ninety Second Railway’.
The title was a reference to what he believed the line would eventually need – trains that ran ninety seconds apart. Or, to put it another way, he was proposing to run 40 trains per hour (tph) on the Victoria line. This was because he was convinced that Britain’s railways were not merely starting to show signs of arresting and reversing their longterm decline in usage. He saw the increasing passenger numbers as a trend that would continue for the foreseeable future. As a result, he predicted that demand would increase significantly on the Underground in the coming years.
The talk was particularly well attended. In addition, many of the attendees were people with detailed knowledge of the complexities of running railways and were familiar with the Victoria line and its particular issues behind the scenes. The audience listened attentively, but it was not at all clear how well the proposal was going down.
The talk ended and it was time for questions. Thanks to the makeup of the audience, these were of unusually high quality and particularly thought-provoking.
Whatever the question, it was accompanied by a general enthusiasm for the ideas put forward. This always came, however, with a caveat – that although such thinking should be encouraged, perhaps the speaker should set his sights a little lower.
There wasn’t complete agreement as to what ‘lower’ meant in this context, but the general feeling was that getting to 32 or 33tph would be an achievement in itself. Some were bold and suggested aiming for 36tph, but at the same time, they cautioned that this was something to aim for, rather than plan around on the assumption it was achievable.
Ultimately, the cognoscenti within the audience seemed to fall into three distinct groups.
Those who knew what had happened
There were those that had seen this all before. These tended to be older men (and they were all men), often retired, who had been heavily involved in the design and building of the Victoria line during the 1950s and 1960s. They were aware of how difficult it had been to achieve what was already in place.
They probably also had a very good idea of what was preventing more from being achieved. To them, the Ninety Second Railway seemed impossible with the infrastructure that existed already.
Those who knew what was possible
There were those that understood what could now be achieved. Generally, these were the modern railway technologists – people whose day job meant they knew the current limitations of technology. This was a time when the latest thing around was the 1992 stock on the Central line. It was also a period when automatic train operation (ATO) on both the DLR and the Central line took years to fully commission and one where cathode ray tubes (CRTs) were the only realistic way of displaying an image of the platform in the driver’s cab. At this point, the Victoria line had been running for over 25 years, entirely underground, yet its trains still couldn’t consistently stop at the same location on the platform without occasional driver intervention. To them, the Ninety Second Railway seemed impossible with the technology of the day.
Her Majesty, Queen Elizabeth II at the opening of the DLRThose who knew what was affordable
Present too were the planners and financiers. They understood how practical it was to get financing for railway projects. The 1990s were not the time to be asking the government for large sums of money for rail schemes in the public sector. Who was going to pay for the extra trains required? For the alterations and expansion necessary in the depot? For the new signalling system that would be required? There were probably those present who argued that getting the money for a like-for-like replacement of the existing rolling stock would be challenging enough.
A success story turned bad
For the first couple of decades, the Victoria line was generally viewed as a success – at least by those on the outside. As a construction project, it had set out with a clear goal and achieved it.
What no-one was really prepared to say, however, was that in one respect the Victoria line project had failed. It had not lived up to expectations with regards to frequency.
Many of the early technical reports (and a range of other sources) make it clear that the line was designed to be a 30tph railway – the ‘One Hundred and Twenty Second Railway’ if you like. Yet all the evidence seems to suggest that, apart from short unsustainable bursts at this frequency, it was quite unable to achieve this. Indeed it would not reliably and regularly achieve this until around 2013 – after the trains and the signalling system had both been replaced.
Why the line’s designers and builders ultimately failed to achieve this provides an insight into what it takes to run a modern Tube at such frequencies – or even at higher ones.
A different world to today
Detailed design of the Victoria line took place in the 1950s. It was a different world. The transistor had only recently been invented (1948) and integrated circuits did not yet exist. ‘Computers’ were extremely common, but not in the way one thinks of them today. At the time, the term generally referred to a person who computes. The electronic variety was very rare and very expensive.
The people who designed the Victoria line were forward-thinking – indeed almost recklessly so. Even with the advance of technology during the construction phase, the electronics were incredibly crude by modern standards when the line opened in March 1969. To put this in context: four months later, man first landed on the moon with only the most basic of computers to assist them.
The limitations of technology meant that the means of controlling a Victoria line train’s speed were crude in the extreme, by modern standards at least. Acceleration was unrestrained, planned coasting and braking was determined by emitted signals at fixed positions on the track and there were a limited range of additional functions to further restrict performance if there was a train ahead. Ultimately this control system probably delivered a better performance than a bad driver, but a worse performance than a good one.
The original rolling stock, pictured at Tottenham Hale. Courtesy OxymanIt was not just the signalling system that relied on the latest technology. The line was the first to have Driver-to-Controller communication (at least most of the time) by means of a carrier wave system. The leaky feeder method of propagating radio waves in tunnels had yet to be invented and was still some years off.
More fundamentally, in the middle of the 20th Century, an electric motor generally meant a direct current (DC) motor. The advancements which led to more sophisticated, more controllable and powerful AC motors in electric trains had yet to take place.
An imperative to reduce staff costs
Despite being hampered by the technology of the day, the planners were also forward-thinking in other related areas. Recognising the need to obtain government approval for the cost of the line, it was seen as imperative that the trains could be operated by just one man (and, again, in those days, it would have been a man). This was intended to reduce operating costs and increase reliability. Moreover, as the 1960s began, it was becoming increasingly difficult to recruit staff for the Underground. Simply paying staff more money was not a realistic option – not least because pay restraint was a key concern of the government. “One man’s pay rise was another man’s price increase”, as Prime Minister Harold Wilson famously said.
Real world insight
It was never never envisaged that all trains would go to the northerly terminus at Walthamstow (Hoe St). Indeed Walthamstow Central (as it would become) was not expected to handle more than around 20tph – well within the capability of a two track terminus. As not all trains would go to Walthamstow Central, and because there was a need to provide access to the depot, a turnround facility was provided at Seven Sisters for trains terminating short. This was relatively well-designed, with a separate platform for terminating trains, but – as we shall see – it wasn’t quite designed well enough.
Meanwhile down south, it must have been immediately apparent to planners that a critical restriction on the line’s frequency would be its ability to achieve the necessary throughput at its southern terminus. Initially, this was Victoria, but the line was always intended to continue further south. The destination finally chosen was Brixton.
It helps a lot when designing something if you can look at a precedent. When it came to Brixton station and the track layout, there weren’t a lot of twin track, dead-end terminals underground to learn from. At the time, apart from the Waterloo & City line at Bank, then run by British Rail, there was only the Northern City line terminus at Moorgate – and the southern Bakerloo line terminus at Elephant & Castle.
Elephant & Castle: the best role model available
The Bakerloo’s southern terminus at Elephant & Castle must have attracted a great deal of attention from the Victoria’s designers. It was certainly the best terminus available for them to draw lessons from. It was also intensively used, as it had to handle all trains on both the Stanmore and the Watford Junction branches of the Bakerloo line. It was just about able to handle 30tph, but even then it was struggling to cope all those train movements. It may be hard to believe now, but 50 years ago the Bakerloo line was the busiest Tube in central London. If the Bakerloo could have handled more trains, there is little doubt that it would have done so. Relief to the Bakerloo line would eventually come in the form of the Jubilee line, which took over the Stanmore branch – a branch which the Bakerloo had itself inherited from the Metropolitan line.
Elephant & Castle was clearly a post-war limitation on the service the Bakerloo line could provide. Indeed at the time, the London Passenger Transport Board (LPTB) were keen to extend the line from Elephant & Castle to a proposed three track terminal at Camberwell Green in order to overcome this. The new terminus would also have brought the added benefit of a long-sought-after station at Camberwell.
What the terminus at Elephant & Castle desperately lacked, in order to provide a useful comparison for the Victoria line, was passengers. This isn’t to say that there weren’t any. Simply that they were not present in anything near the quantity expected on the Victoria line then (let alone what it sees now). This is because, even then, the Bakerloo had largely acted as a connection between the suburbs of north London and central London itself. Southbound, then as now, the majority of passengers would have alighted by the time trains passed Waterloo.
Indeed the Bakerloo was only really extended from there to Lambeth North station in order to reach the depot at London Road, close to St George’s Circus. Having reached that far, it made sense to take the line a little bit further to Elephant & Castle and at least try to tap into the limited extra traffic this would bring. This lack of passengers explains why, practically since opening, there have always been proposals to extend the Bakerloo line southward.
A schoolboy error?
With a lack of passengers in their best example, it is hard to see how the Victoria’s planners could accurately factor the human element in their calculations.
This isn’t to say that they didn’t try. Various exercises were carried out involving simulated crowds. Unfortunately, these made the schoolboy error of… well… using actual schoolboys – a group of people who can hardly be said to represent a meaningful cross-section of Tube travellers. The line’s planners were not blind to this, and there is sufficient evidence to show that they attempted to adjust their data to reflect typical Tube users. A more representative group of test subjects, however, would likely have been more useful. Perhaps it was just too difficult to organise or, perhaps more likely, it was deemed too expensive to conduct the trial with more appropriate stooges.
Another possible reason for overconfidence, later on, was that a lot of reliance seems to have been placed on experience gained elsewhere – with the 4-car Victoria line trains that ran an early shuttle service between Woodford and Hainault on the Central line.
This may well have provided the planners with a lot of real world experience on the engineering side of things. However, it was also a lightly used open-air section of the Underground serving five stations and including what was then the least-used section of the network. As a result, it was hardly going to provide the stress testing needed to ensure you can run 30tph.
Getting things right
This is not to say that the Victoria line planners didn’t get a lot of things right. The termini at Walthamstow Central, Victoria (temporarily) and Brixton had long crossover tunnels outside of the stations. These enabled a fast approach to the platforms. The stations also had long overrun tunnels, so there was no need for the signalling system to restrict the speed of approach (in case the train failed to stop correctly). Remember that they were relying on the train stopping automatically and sufficiently accurately – and they had already factored in having all platforms being longer than the trains to cater for any resulting margin of error.
In addition to the attention to detail paid to the track, the performance of the trains themselves was not neglected. Unfortunately, in those days, all that could be done to improve performance was to have more motored bogies. This was done, but one can only go so far with it. This is because, with each powered bogie added, the benefit, as measured in time-saving, goes down, whilst the weight penalty of each additional bogie remains constant.
The Brixton loop
It isn’t clear whether the planning for a fast terminal turn-round time was deficient, whether the measures in place simply turned out not to be enough or whether they were sufficient for 30tph but other factors restricted frequency. Whatever the case, the first proposal to build a loop at Brixton via Herne Hill (where there would be a single platform station) was not long in coming. This in itself seems to suggest that, at one point in time at least, the terminus at Brixton was the primary limiting factor to frequencies on the line.
The suggestion, taken quite seriously in the 1980s, was to have a loop at Brixton, rather like the Kennington loop on the Northern line, so that trains could continue from a southbound platform and reappear in the northbound platform without having to reverse direction. As Piers Connor reports, the idea was abandoned for two reasons. The first was that it would have required two extra trains. The second was that the crowding caused by the expected number of passengers added by a loop station at Herne Hill would have eclipsed the relief benefit provided by the loop itself. This was hardly the desired result.
Interestingly, it seems that no consideration was given to providing a loop at Brixton without a station at Herne Hill. This would have probably have obviated the need for a least one of the extra trains, but the relief gain would have been small in proportion to the still-large tunnelling and fit-out costs. Without the up-tick of passenger fares a station at Herne Hill would have provided, this meant it would probably have failed any business case or financial scrutiny.
The theory
Aside from the loop, Piers Connor also reports on frequencies achieved on the Victoria line in the 1980s. In particular, in part 6 of his articles on the Victoria line in Underground News (sadly not all parts are available online) he states:
From 1975, the Victoria Line service was increased to normally run with 34 trains during peak hours, although this dropped back to 33 between 1979 and 1985. The service was generally based on a 126-second headway, with a 120-second headway during the 20-minute ‘peak within the peak’.
Now, as Sir Humphrey would say, these figures are liable to be misinterpreted.
Firstly, there never was a 126-second headway. The Victoria line, for most of its life, has run to a timetable specified to the nearest quarter of a minute. 126 seconds equates to approximately 28.5tph. In reality, it was a timetable where roughly two out of every three trains at 120-second intervals whilst the third train had a 135-second interval. In addition, approximately two out of three trains would go to Walthamstow Central and one would terminate at Seven Sisters. Quite surprisingly, the timetables of the day suggest this is just a coincidence and the turnout at Seven Sisters did not cause a delay.
Secondly, it is worth pointing out that the ‘peak within the peak’ lasted for only 20 minutes. This was a short term burst, possibly only in one direction. It was clearly not sustainable or it would have lasted longer. A 20 minute peak on a line with an end-to-end running time of over half an hour naturally suggests some tweaking to the basic timetable to get a very slight improvement of frequency. Indeed in terms of capacity, it is not even equivalent to half an extra train during that 20 minute period.
What Connor does not make explicitly clear is that this frequency was not subsequently achieved in later timetables. In all probability, the increase in passenger numbers also increased dwell time and prevented the more frequent service. So it may well have been that later the limiting factor became the dwell time at Victoria station (northbound), especially as there was an initial reluctance to temporarily close the platform to people entering the station to reduce overcrowding.
The practice
Mike Horne, who was a manager on the Victoria line during his career, paints a very different picture from that given by Connor. It is certainly a less positive one. As he writes online:
The Victoria Line that I knew and for quite a while worked on was a pig of a thing. It was being pushed well beyond the expectations set for it when it was built and was running a 2 – 2½ minute service, or about 27 trains an hour, in theory. This was more than it was designed for and only the infiltration of 1972-stock cars off the Northern Line allowed the fleet to be topped up to provide sufficient trains (24 trains an hour was the most originally contemplated). The signalling and automatic train control systems did not work well with such intensity. The slightest irregularity would cause a train following too closely to just catch a 270 (restricted speed) code instead of a full speed code, and condemn it to run at controlled speed into following platform, perhaps losing it 10-20 seconds, depending on location. This cost capacity and reduced effective throughput. The track layout was hugely inflexible, especially at Seven Sisters, and any significant delay would cause mayhem with the service as the controllers and crew managers battled to sort things out. The railway was working at its limits, so when something went wrong it had a disproportionately big impact. The service either ran well, or was dreadful. It was hard to be in between.
In a modern day equivalent to John Self’s talk from the 1990s, the article is entitled 33 Trains an hour – but why not 40?
As Horne indicates, by the time the 1967 Tube Stock was withdrawn the Victoria line service was running at only 27tph. This was achieved by running the trains 135 seconds apart, regardless of destination. By now the line had 37 trains in service thanks to butchering some Northern line 1972 Stock, yet as can be seen, this was providing a worse service than had been delivered with just 33 trains 30 years previously.
The trains
When the time came to replace the Victoria line trains consideration had to be made as to how many units to order. The 1967 Stock consisted of 43 trains, of which 37 were generally in service during the peak. With better analytical tools than before available, it was concluded that a 33tph service was achievable. This was 10% better than the best achieved previously and around 22% better than was running at the time.
A further complication was that by now the Underground had entered the era of Public/Private Partnerships. The nature of these deals discouraged risk-taking – such as planning on running driverless trains or aiming for too high a frequency. This was because the financial risk of failure for the private contractor would rarely, if ever, eclipse the likely uplift in the farebox. Indeed this “play safe” attitude would ultimately lead to the private company responsible for upgrading the Victoria line (Metronet) ordering more trains than it really needed. After all, it was a cost that could be passed on to the ‘customer’ (London Underground) with few – if any – repercussions.
Nonetheless, this upgrade should at least have yielded 33tph on the Victoria line, then seen as the likely maximum, and that should have been the end of the story.
28.5tph
The first stage of that upgrade was simply (and we use that word advisedly) to replace the trains with the new purpose-built modern 2009 Stock and the signalling with a state-of-the-art Westinghouse (now Siemens) system called Distance-To-Go. During this period, the new trains were effectively ‘slugged’ due to external restrictions on power supply and the need to co-exist with 1967 tube stock which was still dependent on the old first-generation signalling.
The 2009 Stock at Seven Sisters. Courtesy Martin AddisonOnce this work had been completed, it soon became clear that the planners of this generation had perhaps been as pessimistic as those of the previous generation had been optimistic. The signalling system was a world away from that which had originally been installed. Despite the DC power supply, the new trains were fitted with modern alternating current motors. One advantage of these is that they are ‘notchless’ – the rolling stock equivalent of being gear-free. It was the equivalent of doing 0-60 in an electric sports car as opposed to a petrol-engined one. In such a situation, the electric car will alway win, because one doesn’t need to go through gear changes.
A taste of things to come was apparent with the first timetable improvement. This was to 28.5tph, achieved without adding any trains to the timetable. 47 trains had been purchased, but the peak timetable needed only 37.
30tph
Things got even better. 30tph would provide a nice, steady pattern of trains 120 seconds apart through central London and this was the next goal. Any variation in this interval at the terminals would simply be compensated for, if necessary, by an appropriate short extra pause at the next station. The assumption (rightly) was that few passengers would notice the extra 15 seconds of dwell time that would result. Impressively, 30tph was also managed without requiring any extra trains in regular service. Understanding the context of what had come before, it should not be understated just how much of an achievement this was. Almost effortlessly, the new trains and signalling had already exceeded the best regular performances ever achieved on the line before.
The big one – 33tph
The really big change, however, was to push the frequency up to 33tph. It is important to note just how this was achieved. At the time, the working timetable was only specified to the nearest 15 seconds. An interval of 105 seconds would have given an even service pattern of over 34tph. This wasn’t, however, what was implemented. Instead, the timetable was altered to run four trains 105 seconds apart, followed by another 120 seconds later. The result was five trains every nine minutes – or the slightly awkward 33.3tph.
That London Underground were hedging their bets on the new timetable is clear from the publicity that announced its launch – or rather, the lack of it. Only after it had been in operation for two weeks did they issue a press release announcing this improved level of service.
The push for more
The successful introduction of 33tph on the Victoria line brought with it an obvious question – could the timetable support even more trains?
It would seem obvious that if you can run four trains 105 seconds apart in succession, then you ought to be able to run five. Why this was not thought possible is a bit of a mystery. In the end, the extra time allowed for the fifth train was removed in 2014. This gave the line a peak hour service of 34.3tph. Despite the slight increase in frequency, the service still only used 39 trains out of a possible 47 in the fleet. Again, bets were hedged. The press release confirming the new frequency was only issued a couple of weeks after it had been implemented.
The push to 36tph
By now it was clear that 34tph (rounding down) was about as much as the Victoria line could take without further major upgrade work. Not least because it would require a move away from a service pattern that regularly saw trains terminating at Seven Sisters.
That shift in service pattern was soon realised to be key. It was a key, however, that could unlock an unprecedented service not just for the Underground but, potentially, the world.
The work at WalthamstowHow those upgrades were completed could form the basis for a major story in itself. The short version, however, is that a working party determined that it was both possible and highly desirable to end the practice of terminating roughly every fourth train at Seven Sisters. They recognised that whilst the old track layout at Walthamstow Central could not cope with this, the modern signalling now could. Also, that the scissors crossover at Walthamstow Central (one of the major limiting factors) was arguably overdue for renewal anyway. By upgrading the crossover and examining the detail of all aspects of Victoria line working, it was determined that 36tph throughout the length of the line was achievable.
Resulting track workSo it was then that on Monday 22nd May 2017 the Victoria line ran a peak hour service of 36tph. This continued for about 80 minutes, a feat that was repeated in the evening peak as well. A long-desired dream of London Underground and the men and women of the Victoria line had finally been achieved.
And beyond?
That is not the end of the frequency story on the Victoria. The plan is to increase the period of 36tph peak running from 80 minutes to around three hours in both the morning and evening peaks. After that, London Underground’s attention will shift to achieving 36tph on the central section of the Jubilee line. The aim is to have this in place by the end of 2020.
Table from paper on World Class Capacity Programme presented to Programme & Investment CommitteeThe obvious question, however, remains: can an even higher frequency be achieved?
36tph means trains are 100 seconds apart. The obvious next step would be to push for 95 seconds. This would translate to a frequency of around 37.9tph – or 38tph when rounding up.
Critically, there would appear to be sufficient trains to run the service – one of the few positive legacies, albeit an accidental one, of the PPP. The current timetable requires 41 trains in service in the morning peak and, curiously, only 40 trains in service in the evening peak – so round trip times of 4100 and 4000 seconds respectively. If a round trip could be done in 4085 seconds then a 95 second interval services would require 43 trains in service. This would still leave 4 spares for maintenance.
Of course, having the trains is only one part of the requirement. As our editor John Bull is prone to point out, there comes a point where frequency is not about how many trains you can squeeze through the tunnels, but about how quickly you can get passengers onto and clear of, the platforms. Nonetheless, it is significant to note that senior people are daring to ask the question. Most notably, Network Rail Chairman (and ex-Transport Commissioner) Sir Peter Hendy, who spoke about it in his keynote speech on The Future of Britain’s Railways last year.
For now, then, last century’s dream of the Ninety Second Railway remains tantalisingly just out of reach. That we now have the hundred second railway, however, is an achievement that should not be overlooked. Certainly, it would have been seen as equally unlikely by the audience of our original talk, and the fact that the Ninety-Five Second Railway seems possible as well should not be overlooked. With that in mind, perhaps we should not bet against our visionary speaker’s dream coming true just yet.
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Brixton loop. Suggest it was taken seriously in the 60s not 80s.
What is it that causes the issues with frequency by terminating at Seven Sisters? Is it the inability to reverse straight from platform 4? Of course you’d then really want there to be a platform both sides of the tracks, so that southbound passengers only had to wait on one- but of course, for passengers, having everything go to and from Walthamstow is better.
With the 36tph timetable, how long are the doors open?
Radical suggestion, but what would be the feasibility of creating extra Platforms at Victoria to allow for alighting on one side and boarding on the other? Cost-wise, I understand that it’s pie-in-the-sky at the moment, but engineering-wise?
Aside from Victoria, which are the two next busiest stations on the line? I’d hazard Oxford Circus and Finsbury Park? Not really feasible at either as you’d kill the cross platform interchange with the Bakerloo and Piccadilly respectively…
PoP
desirable to end the practice of terminating roughly every fifth train at Seven Sisters … except that it often felt like every third or even second train ….
What’s worse, there seemed to be no pattern to it & the unpredictability, from a passenger’s pov, did not help[ – the points-reconstruction & upgrades have killed all of that, I’m glad to say.
As you say, the problem with a 90-second railway is station dwell times, especially at/in stations with non-regular passengers, from outside London …
And the Vic-line has FIVE of those [ Tottie Hale / King’s Cross / Euston /Oxford Circus / Victoria ]
Al__S
Because, so many people now want to go to any of the three further stations:
Tottie Hale for Cambridge/Hertford/Stansted trains, Blackhorse Rd for the GOBLIN & Walthamstow for the myriad buses,
– That terminating at Seven Sis is a waste of time & space.
Sean
I’m given to understand that “space is tight” underground at VIC to the sides of the existing station – basements / piling / services of other buildings – I think more information on this might be useful.
@Greg T – You are right about Vic being tight – I shared an office with the Scott Wilson project director who was managing the upgrade and the flow of bad language at design stage because of the difficulty of fitting everything in (especially the links to the District from the Victoria) was entertaining (and matched only by my own weaker efforts in relation to mopping up after a bodged French attempt to design a tramway for Vilnius). The considered view of my engineering and pedestrian modelling colleagues on the upgrade was that there was no further scope for expansion at all.
At those stations with unusually high numbers of bewildered/jetlagged/encumbered punters, the issue may well be more a case of wider platforms, and setting back PIDs away from the rail edge of the platform so that the luggagistas can stand further back whilst they sort themselves out.
@Sean – a view that, for instance, topped RATP’s wish list at the time of planning the RER network – but even the French couldn’t afford the platform separation.
Is there a reason for not explicitly naming this Victoria line manager?
I’m surprised the article does not cover the stations themselves – many (e.g. Vauxhall) weren’t built with sufficient capacity and have subsequently required expensive upgrades, which may have also impacted on the headways
Excellent article, thanks.
A number of points if you don’t mind:
The nadir of passenger numbers was in the early ‘80’s; passenger numbers were already climbing strongly by the time the former GM gave his prophetic talk.
The addition of the 1972 stock trains in the mid-80’s was in response to the growing numbers. The project included some signalling tweaks and additional sidings. The cunning part of the conversion is that the 1972 stock cars were never at the outer ends of trains so no cab modifications were required.
The inaccurate stopping was tamed in the early 2000s with the installation of the third generation autodriver box. There were, originally three service braking rates – low, normal and maximum – controlled by mercury in inclined tube retardation controllers (retarders). The first and second auto driver boxes commanded one of these brake rates and then compared the retardation sought with what was provided. With just three brake rates and an inevitable mismatch between when were effectively two closed loop control systems controlling the brakes, stopping inaccuracy was the inevitable result. The third generation auto driver box bypassed the retarders and controlled the brake valves directly – a single closed control loop. Accurate stopping was achieved at last. (The retarders were retained for so-called coded-manual operation.
1967 tube stock also suffered slow and sticky doors which didn’t help to keep dwells to a minimum. One of the reasons for increased round trip time over the years was the increasing dwells which were seen throughout the tube because of the increasing customer numbers.
Moving on to the new trains:
Their performance was not “slugged” during the inter-running period. The only adjustment was to limit the voltage allowed to be used in regenerative braking. If trains arrived at a station a bit early, they were held. This caused complaints because the lack of regenerated energy caused the trains’ braking resistors to heat up and, being force cooled, the heat was dumped into stations during the dwell. There were a lot of complaints. The problem evaporated within days of removing the last 1967 tube stock when full regenerative braking was implemented.
A significant improvement with the new trains was also wider doors which worked a little faster and more consistently. Once a few changes were made to allow staff to manage activations of the sensitive edges, I reckon that positive door operation is one of the bigger benefits of the new trains.
You mention the improved performance of the trains – not least six motor cars rather than four – which allows increased acceleration. Top speed was virtually unchanged. However another significant improvement in performance was delivered through an increased braking rate which is the highest rate used anywhere on the underground.
How much would fixed door opening times (as practised in some driverless systems, such as here in Singapore) help reduce headways?
It’s handy that the 2009 stock provision was so generous initially, especially as the bodywork design is pretty unique. The 1995 stock provision was pretty generous too, enabling frequency improvement on the Northern Line within the existing fleet, whereas the 1996 stock was subsequently lengthened to 7 cars AND topped up with an additional 4 trains…
Anonymous of Croydon,
No I do mean the 1980s. There seems to be a technical glitch meaning the links have disappeared. I will try and reinstate them later today. The link to Piers Conner’s articles will make it clear it is the 1980s.
AL__S
I don’t think terminating at Seven Sisters caused problems, as such, with the 2009 stock. For the 1967 stock read the quote from Mike Horne.
The issues were that Tottenham Hale and Walthamstow could ideally have done with a more frequent train service and by the time you detrained at Seven Sisters and did a shunt to get back to the southbound line you might as well have gone all the way to Walthamstow (just 5 minutes journey time further).
Sean,
One of the problems with having a platform on each side is that it only works if it is done at the busiest station – and then it transfers the problem to the next busiest station. Currently that is Victoria (northbound) but King’s Cross (southbound, I think) can be almost as bad. To do enough stations to make a difference, if possible, would be so expensive you would be better putting the money into building a relief line.
Malc,
The reason I have not mentioned the name of the manager is because I am not 100% sure. I am reasonably confident it was a guy called John Self but I am not sufficiently confident to state this categorically in the article.
100andthirty,
As always thanks for the insight. As regards “slugging”, that is what was reported at the time because, I believe, it was necessary due to the trains having to be compatible with the old signalling system. I didn’t mean to imply they couldn’t be driven as quickly just that they couldn’t normally achieve their best performance.
I will think about rewording this.
Mikey C,
I would strongly contest your statement about the Northern line 1995 stock although I agree with everything else.
The Northern line was supposed to have an upgrade consisting of new trains followed by new signalling. They bought sufficient trains for the increase in frequency possible with the new signalling. The government reneged on paying for the signalling so they had far too many trains. This was resolved only when the Northern line finally went to ATO. Now, because the modern signalling is better than that proposed in the 1990s, they don’t have enough trains. They will achieve a little more with even better stock utilisation but basically they could do with more trains – and space to store them.
Doesn’t the Paris Metro or the Munich S-Bahn achieve similar levels of frequency?
In terms of finding out what is _possible_ rather than just seeing if five seconds can be trimmed, is it ever done to run a service from end to end, stopping at each station for the minimum time to open & close doors, ie with zero dwell time due directly to passengers?
One could then make a better estimate of what the actual limit would be instead of some theoretical calculation of the perfect passenger.
Re 130 and PoP,
“Slugged” Didn’t the 3rd/4th rail voltage also increased around the same time as ’67 stock withdrawal and the reduction in number but increase in size of 3rd/4th rail sections and the increase from 3500A to 4500A max traction current effectively equate to some kind of un-slugging upon the ’67 stock withdrawal?
I think the Queen is at opening of the Victoria Line rather than the DLR. The kit looks 1960s and her dress is also of the period.
what effect will Crossrail2 have on the loading of the Victoria line from the Sevensister-South Tottenham CR2 station to the St Pancras-Euston CR2 station and also Wood Green CR2 station on passenger transfer from the Picadilly at Finsbury park
Re Alison W,
They already have that data, the maximum doors open for passengers time implied from that was discussed in another LR comment thread (not the previous Vic Line Walthamstow article) which I can’t seem to find now, along with the conclusion that many people wouldn’t be able to get on at some stations at certain times. if the tph was increased.
I suspect (/hope!) that performance at Victoria should improve as the scheme moves towards completion and pedestrian flow vastly improves so passengers are less concentrated at certain points on the train /platform. Hence until the Victoria works have completed and things have settled down it isn’t worth contemplating any changes in practice rather than theory.
The opening of Crossrail may also improve the Oxford Circus situation as regards reducing Central line users /interchangers and Bakerloo users to/from Paddington thus making the station slightly less of a nightmare.
AlisonW… There’s enough confidence in modelling not to need to do a physical run to confirm the round trip time without opening the doors at stations. LU has huge quantities of data about station dwell times, line by line, hour by hour and day by day.
PoP… The manager was John Self.
Re “slugging”, the old signalling – principally the layout of the old block sections – will have imposed constraints on the new trains even though the new trains were operating using the new “Distance to Go” system from the beginning. The replacement of the old track circuits with the new ones to revised spacing removed those constraints. My point was that the traction performance settings weren’t “slugged”.
ngh…..the original upgrade scope (to get to 33TPH) was for no nominal voltage increase but that current would be increased to 3500A. This plus low loss conductor rail, where necessary, was intended to provide “enough” power. You refer to the voltage being increased after the last of the old stock was withdrawn. The supply voltage wasn’t increased, but the trains were set to allow a maximum regeneration voltage of 790V. Clearly this will have caused the average voltage to increase. This would not have affected train performance as the ac drives are effectively regulated power supplies.
With the “upgrade 2” to get to 36TPH there have been further changes to deliver the increased service without a proportional energy increase. These have mainly been about extracting the maximum possible regenerated energy. This was all being scoped as retired. I don’t recall whether the trains were capable of withstanding either 4500A or 750V. I vaguely recall that they might have been OK on the higher voltage and they might have allowed a higher current ceiling only on braking. All this was being talked about, but I don’t know for sure what exactly was implemented.
Off topic, 750V and 4500A are firmly in the Sub Surface plan and (for PoP), S Stock performance is “slugged” at C stock acceleration with A stock top speed until the new signalling is implemented.
RE 130,
Trains were ordered as 750V capable and they have the same inverter tech as the S Stock and 379s, 377/6/7 and 387s (but 345 are different) so will be fine for 850V 3rd rail supply voltage.
2500A / 3500A / 4500A being the maximum current per transformer in the substation and hence traction circuit.
From what I understand: regen was later upped from 790V (with 33tph at end of original upgrade programme (VLU)) to 890V for WTT 37 (the last changes pre night tube which was WTT 38). Current limit was upped from 3500A to 4500A for WTT39 changes (36tph) for VLU2.
“The supply voltage wasn’t increased, but the trains were set to allow a maximum regeneration voltage of 790V. Clearly this will have caused the average voltage to increase. This would not have affected train performance as the ac drives are effectively regulated power supplies.”
But the supply voltage does affect whether the power was actually available at the point along the line where the train is given there will be several trains per transformer circuit as well as regeneration going on. The ’09 trains are 1.8MW max traction power + auxillaries so 750V @ 4500A is circa 3.375MW just enough for 2x ’09 stock drawing full power with no regeneration per traction transformer circuit.
890V as a magic number originates from some work NR and Southern in 2004 on the early 377s on regen.
I have updated the article to reinstate missing links. Now that the name of the speaker in question has been confirmed I have referred to him by name. And I have reworded the reference to “slugged” to make it clear that it was not the traction itself that restricted performance.
On the subject of whether or not the Victoria line is the most frequent service, I believe that it is certainly the most frequent in Western Europe that operates on a twin-track railway. Paris has claimed that Ligne 1 can operate at 85 second intervals but my understanding is that this is purely theoretical and, until they get around to buying sufficient rolling stock, they actually operate at 115 second intervals.
Worldwide, only Moscow operates more frequently but with acceleration and braking rates that would not be tolerated in this country. I notice the title of the article has been changed to “Making the Victoria The Most Frequent Metro in the world” but this has to be interpreted as an aspiration and not where we currently are.
ngh…….this is a debate probably better lubricated by a pint!
I have to say that the trains ordered by Metronet in April 2003 were not required to be 750V capable. The whole power question was one of those things that fell between the PPPs and the Power PFI, and there was a big dispute over it a couple of years later. I wouldn’t be surprised if the trains were always 750V capable, but that wasn’t what was asked for and was, for the 2009 tube stock at least, declared not to be possible without modification. It was circa 2007 that the decision was made to increase the voltage on the Sub Surface lines to 750V.
You’ve mentioned 3500A and 4500A as maximum transformer current in the substation. I quoted those values as the maximum current each train can draw from the current rails. Originally these values also applied to how much current could be put back but it was later recognised that there would be no harm in putting back more current if the train’s regenerative brake was capable of generating it. Don’t be fooled by the quoted motor rating of 75kW (24 motors x 75kW=1.8MW), it is the nominal or continuous rating. In metro applications the motor continuous rating generally has little or no meaning; the motors will draw more current (accelerating) or deliver more current (braking) than the rating would suggest.
I concur that if the power isn’t there, the trains won’t perform, but the point I was making was that there is an enforced ceiling on performance which won’t increase if the voltage or current increases. This is different from how the old DC traction systems worked where they would respond to more power; something that tended to agitate signalling engineers who worried about trains breaching calculated overlaps. They got excited about the plan to increase the Sub Surface Railway to 750V until they were told about the “regulated power supply”.
100andthirty,
Not disagreeing with you about the decline in usage having already been arrested and reversed in the 1990s. What I think was still in doubt at the time was whether it would simply revert to its previous highest level or whether it would continue to rise beyond that.
I cannot recall others in the 1990s suggesting it would go way beyond what we have seen before so I think the speaker deserves a bit of credit for his vision (or lucky guess) there. I now realise I hadn’t made this clear so I have reworded this.
Graham H,
The late Bill Clarke of London Transport once explained how, theoretically, after lots of objective analysis, the size of transport projects were decided on and how they got approved.
He then scuppered all that by telling us what actually happened was that soundings would be made to find out how much they could probably get out of the government – a figure that was always much less than what was really required.
The figures justifying the project were then not so much massaged but completely changed as necessary to suggest that, for the amount of money they thought they could get, a totally satisfactory value-for-money solution could be developed.
33.3tph was run as part of TfLs usual sensible phased implementation – ensure you can cope at that level before going further rather than diving straight in.
It is strongly felt that 36tph is the max with two platform termini, and especially with the current platforms and dwell times. It will also be interesting to see the approach to the Jubilee, and whether end to end running will come in as higher frequencies are introduced
An interesting article as ever. As a long time Victoria Line user a few comments.
It certainly would have been John Self as GM. A jolly decent chap who even managed to bear my occasional moans about the service with good grace. 😉
From memory the Tube reached a record high patronage level in 1987/88. This was associated with the economic boom post various privatisations and deregulation. I can remember the agonies it caused inside LU as the extra usage was really showing up the creaking nature of the system. The other side of the coin was that the system had not had any consistent funding from the GLC or government for many years which made it impossible to do anything remotely sensible. There were multiple TV programmes and news features which involved Denis Tunnicliffe and Sir Wilfrid Newton practically pleading with the Govt to do something via the TV cameras. I am sure there is a relevant Thames News video on Youtube with SoS Paul Channon dismissing the pleading with the usual “we spend lots on the tube” flim flam. And then the Kings Cross Fire happened. The economy also wobbled somewhat and then had real nightmares in the 90s (Black Wednesday etc) so the issue about how sustainable the upward trajectory on demand was would have been a real point of challenge between government and LRT’s management. As I have said before the Govt were terrified about being blamed for the Kings Cross Fire (or anything that happened afterwards) so money “fell from the sky” to deal with identified safety inadequacies but LU had limited capacity to up the throughput of projects sufficiently quickly. You don’t suddenly find lots of qualified project managers, architects and engineers in a broom cupboard at 55 Broadway.
I don’t really like to disagree with Mike Horne but as a regular user I’m pretty sure we got a 2 min headway a lot of the time in the peak between Brixton and Seven Sisters. I do agree with his comment about “it was either good or dreadful”. Much of the time the “old” Vic Line worked pretty decently and was not in the league of the “never quite finished” upgraded Central Line or “misery” Northern Line. However if you had a horrendous service on a Monday this often meant the service was a write off for the week. I never really understood why this happened but having a “week from hell” as a commuter was not unknown. Things like crew changes were also very sloppy back then – as if no one cared that hundreds of people were on a train going nowhere while a driver ambled up the platform as slowly as he could. It is *vastly* different now.
I was lucky enough to get a cab ride from N Park to Warren St when the 09 stock was in use. I’d arranged a depot visit before I left LU as N Park was the first depot I ever visited (completely illicitly within weeks of arrival in London – those were the days!). At that point in time (early 2012) the switchover between “new” and “old” signalling was just south of Euston and the difference was noticeable as we passed over the transition point.
Thankfully I don’t really see the peak very much on the Vic these days but what is very noticeable now is that the increased frequency and much higher service quality has been hugely generative in terms of usage. I can recall that off peak you’d be lucky to get 10 people waiting at Blackhorse Road on a 2-4 min headway. Now with trains every 2 mins you’ll easily be into double figures for every train. It’s even more pronounced further down the line. The other thing that has changed hugely is usage between stations outside Zone 1 on the north end of the line. The Overground hub at Highbury has massively changed usage patterns and the numbers of boarders and alighters. To a lesser extent the growth in the Lea Valley has transformed usage at T Hale but that’s been over 2 decades. Overground on West Anglia and the GOBLIN has changed things at Seven Sisters, Blackhorse Rd and Walthamstow Central. The sudden discovery that places like Waltham Forest, Enfield and Harringey boroughs existed has also accelerated the housing market and demographic changes with much more to come especially through T Hale.
There is no doubt that the Vic Line has been transformed from what I saw for the first time back in 1983. I do think it faces a number of challenges. One is station capacity – the earlier remark about platform width is spot on. Many platforms are now far too narrow even off peak. The peak doesn’t bear thinking about at places like Finsbury Park. Getting people in and out was / is also a major issue at many stations in the peaks. The other major issue is maintaining the quality of service. The signalling system and track seems to have a dreadful “wobble” every few weeks suggesting something isn’t quite right in the maintenance regime. I do wonder if the track is literally being “bashed to bits” from the intense service levels. High intensity automated service with trains doing the same thing repeatedly with no driver variability can cause real issues with track wear. The other aspect is that the trains and systems will wear out and components will become obsolete and therein lies the ongoing maintenance and renewal challenge given no major money is going to be spent on the line for a very, very long time. Far too many other lines are ahead of it in the queue for the meagre financial scraps from Mayor Khan’s table.
Re 130
Agreed my usual rule is normally not to go better than back of the envelope numbers for LR comment purposes and not to get too verbose. With VFDs pictures/graphs are usually worth at least a thousand words and this isn’t a simple topic… (I do earn some of my crust advising VFD manufacturers)
For a suitable fee… probably just changing the number in Mitrac. Increasing conductor rail supply voltage is key to reducing I2R loses as well as increasing availble power.
The limit is set by the circuit breaker on the transformer/rectifier in the substation.
But only circa 20% more before you run into motor and electronic cooling issues. It also needs other trains capable of absorbing the regenerated power i,e, accelerating. Getting the time table to optimise what all the trains in an electrical section are doing accelerate / coast /decelerate (regenerate) is a key part of the ability to get the VLU2 outcomes without massive extra spending on the electrical supply.
very different to the case on NR where everything 3rd rail has to be software slugged to limit current draw (same traction electronics in many cases as ’09/S Stock cases) but less so on return. The maximum per transformer/rectifier where NR traditionally used 3500A output transformers/rectifiers but now usually 4000A on NR with 2 per substation.
Pseudo regulated if the conductor rail voltage is lower than the DC link voltage then it is below the “regulated” level, it effectively caps the max unlike traditional DC motors and control (keeps the signal engineers happy) but doesn’t regulate on the low side, the aim being to run the motors at fixed voltage to improve efficiency unlike DC. Expect to see a nice improvement in performance on SWR when Durnsford Road area finally gets upped to 750V after the D stock withdrawal as all the SWR AC tractioned stock is operating well below the DC-link voltage currently (but less so after the upgrade).
VFD – variable-frequency drive, a type of adjustable-speed drive used in electro-mechanical drive systems to control AC motor speed and torque by varying motor input frequency and voltage.
Re LBM,
” by varying motor input frequency and voltage”
The aim is to keep the voltage constant (at the ideal voltage for maximum motor efficiency) but just varying the motor speed via changing the input frequency and allowing the motor to draw as much current as need up to a set limit. Virtually all rail applications use Asynchronous motors so the supply frequency has to be just higher or lower than the desired motor rotation frequency.
WW
You don’t suddenly find lots of qualified project managers, architects and engineers in a broom cupboard at 55 Broadway.
Or, on another topic, electrification & signalling engineers for what used to be “BR”, either – something a certain Mr G refuses to notice.
There is no doubt that the Vic Line has been transformed from what I saw for the first time back in 1983. I
You should have seen it when it was only Walthamstow-Highbury, then (!)
Which reminds me: The crowdings below ground at Highbury & Walthamstow are getting worse, especially the former. The “paring” to get it past the Treasury back in the early 60’s is now showing with only Two escalators at each place & crowding at both top & bottom of said places.
[ Highbury is IMHO, more easily “sortable” as the old station-site across the road is still available. ]
NGH
Expect to see a nice improvement in performance on SWR when Durnsford Road area finally gets upped to 750V
What area does Durnsford road supply, these days?
@Greg T
Ian Visits has an informative write up of the plan to increase passenger capacity at Highbury & Islington station: https://www.ianvisits.co.uk/blog/2017/08/06/new-entrance-planned-for-highbury-and-islington-station/#comment-121143
The plan is to reopen the Northern City line station across the road. When the Victoria line opened in 1968, they closed the Northern City line entrance, and it’s been closed ever since.
@ngh
Interesting. In another life I used to work on avionics diagnostics for a variable speed constant frequency (VSCF) electrical power generation system for MD-90 aircraft (the follow on model from the DC-9) – which worked in the opposite direction, generating constant voltage and AC frequency from the jet engines. It never worked reliably however in early service, due to hardware problems. After I left the project I haven’t kept up on its performance.
ngh,
It also needs other trains capable of absorbing the regenerated power i,e, accelerating
But only because the infrastructure can’t send the generated electricity back upstream because the installed sub-stations are incapable of doing this. It is not fundamental and one day when substations get upgraded or replaced we can expect to see such restrictions removed.
Re Greg,
Durnsford Road: SWML and District Line Wimbledon Branch
The lower DC link voltage used on the future new Aventras might also have an interesting effect on units 3rd rail performance.
Re PoP,
“But only because the infrastructure can’t send the generated electricity back upstream because the installed sub-stations are incapable of doing this. It is not fundamental and one day when substations get upgraded or replaced we can expect to see such restrictions removed.”
Substations designs that do this are beginning to be able to do this but only from some manufactures and they also require other power distribution changes they are also a lot more expensive. Resistive loads are used to absorb excess regenerated power in other countries but that is much harder or impossible underground in London due to cooling issues (e.g. the resistors would have to be above ground remote from the substation so a high installation cost.) and these tend to be on new build installations.
Substation design tends to be based on proven reliable solutions not innovation.
QTR
It is strongly felt that 36tph is the max with two platform termini, and especially with the current platforms and dwell times.
Fully understand your sentiments but then people thought 36tph would be impossible for the same reasons. What is not possible now may not be the case in the future. You highlight dwell times.
To my naïve mind it wouldn’t be that hard to improve dwell times by five seconds if one concentrated on the door opening and closing sequence. For example:
1) have doors open automatically as on Thameslink could easily provide a potential saving of 1 second.
2) if mindsets could be changed one could initiate the door opening sequence once it was established that the train had almost reached the prescribed place on the platform and the train was travelling sufficiently slowly. I believe something similar is done on the Paris Metro where the doors unlock just before the train stops. Maybe save an extra 2 seconds.
3) Use the limits of material science to make the doors lighter but equally strong. This means you can open and close the doors faster. So maybe an extra second gained on both opening and closing giving 2 extra seconds.
Of course having got your extra 5 seconds and approximately an extra 2tph you need to look at other factors (e.g. heat, stepping back) yet again.
ngh,
But such substations are a fundamental part of the New Tube for London plan. So once they are used for that they will, hopefully, be seen to be a proven reliable solution and not innovation.
Apparently Jonathan Roberts was there at the original talk although I am starting to wonder if this talk was made on a number of occasions.
Remarkably, he has a coaster associated with the talk. It states
Victoria line
To be the 90 second railway
where every second counts
and people matter.
PoP
You beat me to it – yes, the Paris-Metro solution, where, if a passenger has pressed the “door-open” button, then they “pop” automatically – but I can bet the Brit H&S people would have conniptions, though.
PoP. ngh… a sub-station that can return power to the grid has been tested on the Victoria line. It fed back the surplus regenerated energy to the LU 22kV main. It’s contribution was noticeable but not huge – about 1GWh/year. This is worth about £75k in saved energy cost and another £200k in avoiding cost of removing the heat from the tunnels. That’s probably enough to “wash its face”. One might imagine that the saving would be bigger but there are enough trains on the Victoria line to do pretty well with absorbing regenerated energy and the whole line normally operates as one electrical section.
To put all this into context, today the annual power consumption on the Victoria line is approximately 72GWh. This is some 16% lower than it was when the line was last running all 1967 Tube Stock. AND capacity has been increased by some 30% AND journey times have reduced (LU presentation to a conference in spring 2017).
Who said you can’t have your cake and eat it?
Re 130,
That sounds about right I’d only expect a small % of the energy put back into the conductor rails not to be directly reused elsewhere with the intensity of Victoria line service.
Any idea whether the alternative DLR supercapacitor trial was useful?
I have added a table giving dates of implementation of upgrades towards the end of the article. I had completely forgotten about this table which can be found in this document.
I have read that the new Victoria line stock is significantly lighter than the trains it replaced. That can only help reduce power consumption.
In relation to reducing journey time, LUL tried to get ASLEF to accept ADO, automatic door opening, three or four years ago. It was opposed on the grounds of deskilling the job. As Pedantic posted, it could save a second or two per train, perhaps 30 seconds a single trip. I understand it is still not in operation. It would be interesting to know if Victoria line management are still pressing for it. The trains are equipped to do it.
ngh, 100andthirty,
But the intensity of the service is not that great on Friday and Saturday nights. I wonder if the figures given reflect the Night Tube. Mind you there is not exactly a shortage of generated electricity in the middle of the night.
To my simplistic mind, if the Victoria line is electrically operated as one section then one such substation makes sense but more than one does not.
Re: PoP – “Worldwide, only Moscow operates more frequently but with acceleration and braking rates that would not be tolerated in this country”
Is this the full story or are there other reasons – possibly associated with LU lessons-learned involvement at its inception? – that enable Moscow to achieve what the best of Western technology cannot?
I for one would appreciate an article on this subject…
Re: GH – “but I can bet the Brit H&S people would have conniptions, though”
It is fairly safe to assume that enabling of doors in this way would lead to an increase in passenger injury, although it might be the case that this would then decrease as familiarity increased (a bit tough on the unfamiliar few who suffer from initial unfamiliarity, or fair game in the name of progress?).
As with all moans about health and safety*, is there any data we could bring to beat on a cost-benefit analysis?
*Somehow the term “health and safety” has acquired a meaning quite distinct from that of the words that make it up; as an initial step I propose deleting the words “health and”, to be replaced with “your and your family’s”, perhaps.
Oops – I meant GT, not GH!
PoP……Anything to do with DC traction is never that simple. Several substations feeding into the section, voltage differentials between supply and train dictating whether there is any regeneration or not, and the point you made about Night Tube all impact on the amount of regenerated energy.
The presentation I quoted showed about 1GWh saving for one inverter and the same again for a second. I am not sure whether they are both in place yet but the presentation indicated one to be in the south and one in the north of the line.
Balthazar: If your speculations about injury and familiarity are both correct, then it might make sense (once the door opening has become automated, if it does) to gradually advance the start-opening time (by software changes) at a rate of, say, 0.1 sec per month – or maybe even slower. Then people would get used to it – like boiling frogs.
@Balthazar -just for amusement, in 1890,the Berlin S-Bahn operated to 30 tph over its busiest stretch – with conventional semaphores, slam doors, and steam traction… I wonder whether we aren’t missing something?
Re door opening – I’ve been on numerous Vic line trains where the doors started to open *before* we came to a stop. Perhaps only half a second, but still definitely when we were moving. Hasn’t happened for a year or so though. Nevertheless, hard to believe an auto opening system could beat that!
I understand that getting to 36tph on the Jubilee is more of a challenge, partly because of the Platform Edge Doors which cause dwells to be a few seconds longer (for the same doors open time).
With a 90s service, how long is the passenger access time, and how much recovery time is left? I can see if a blocked door causes a 10s cycle time, you’d end up with a 80/100s interval which would escalate with classic bus bunching problem.
I worry that TfL aspire to accuracy that the real world can’t match, and you’ll get all the thrashing/jitter problems that have bedeviled computer performance for decades.
I do find all this “electricity talk” fascinating but it completely flies over my head. That is not a criticism of those doing the discussing btw, more a reflection of my extreme dislike of physics at school and disinclination to ever get my head round the mysteries of electricity. One day I might understand it. Oh and no one need try to explain it here either – it’d send the comments completely off topic. 😉
@Balthazar:
An interesting article (auto-translated from Russian here on the limits of performance on the Moscow Metro includes a table and graph of the relationship between acceleration/deceleration and theoretical maximum trains per hour – eg. acceleration of about 1 metre per second per second (which is apparently the average (not maximum) acceleration of typical Moscow metro trains) gives you a theoretical maximum of 47 trains per hour (which translates to an actual service of 40 trains per hour once allowance is made for real life running conditions). Deceleration is apparently about 1.25 times the acceleration rate.
My observation from visiting Moscow was that the drivers are very assertive at door closing – when it is time for the train to leave they will close the doors regardless of whether people are still trying to board. It would be interesting to know how many accidents happen due to people getting caught in the doors (and due to people falling over when the trains accelerate and brake, for that matter).
@John B: The article suggests in Moscow they overcome this problem by not running the trains at maximum speed so there is a reserve that can be called on to overcome short delays:
Unplanned delays of subway trains at stations during peak hours occur regularly and range from 5 to 10 s. In order to be able to “fit” the schedule, the mode of the metro train must be such that after a delay it can travel 5-10 seconds faster than scheduled, and compensate for the delay. If this “power reserve” is not available in the timetable, stable operation of subway trains on the line can not be guaranteed.
@ Greg – well LBM has pointed you to the possible works at Highbury. Anything at Walthamstow is partly dependent on that dreadful proposed development in the Town Square which might give a new accessible link into WW Central. Unfortunately none of that fixes the platform width issue at places like Victoria, Green Park, Oxo, Euston etc. That’s going to be a real killer if growth continues.
The other factor we have over the next few years is the gradual expansion of the rail network in London and addition of new links and extensions. Each time this happens you typically get a reshuffle of travel patterns but also a ratcheting up of overall demand because new / different trips become feasible. While I can see some changes possibly pulling demand down on the Vic Line in some places I can also see plenty to drive demand ever upwards. I’m certainly not convinced that Oxford Circus is going to see much relief – especially if there is an out of station interchange between Oxo and the Hanover Square entrance to Crossrail.
@ Balthazar – re Moscow. I did some hunting around on the web to answer a question JB set about tph on Metro systems before he set the title for this article. Unless you are fluent in Russian there is not very much detail about the Moscow Metro and what there is hard to verify. Surprisingly (to me anyway) a fair amount of official reports are released about development of the Metro and how projects are progressing. However the pdfs are all in Russian and Google translate can’t translate them. The web page links were translated hence how I know what is released. There wasn’t anything in their recent news articles either although the new City Circle railway in Moscow is seemingly doing very well.
I’ve never been to Russia so I have no direct experience of their Metro and while I once dragged a party of Moscow Metro officials around the Underground with the aid of an umbrella (held high in the air) [1] we didn’t get a chance to share stats or ask probing questions. Unless we have a fluent speaker and reader of Russian among the LR management or readership I think a comparative article to LR’s usual standards is a very big “ask” indeed.
[1] oh the glamour of my old job. 😉
Re WW,
“Unless we have a fluent speaker and reader of Russian among the LR management or readership I think a comparative article to LR’s usual standards is a very big “ask” indeed.”
I worked in Moscow once upon a time and can translate, I suspect Graham F can help too.
The lesson from Moscow is to stand feet wide apart looking out the window or you will end up on the floor – though this could get sorted with software control to eliminate ms^-3 issues aka “jerk” (and final friction brake application on deceleration).
I started trying to collect Moscow metro technical info a while ago as I wanted to compare UK and Moscow acceleration curves but didn’t get that far.
A few points to note:
1) The 36tph frequency at Brixton alternates between 90secs for the non-conflicting crossover movement, and 110secs for the conflicting crossover movement. The headways are altered to/from 100secs at Stockwell. This is a sensible move to make turn-backs more reliable.
2) The platform re-occupation time is at best 45secs. This is a limiting factor in improving frequency beyond 36tph, as you also have to factor in dwell times and operating margin.
3) The Moscow Metro manages 95sec headways, Kiev 90secs, and in the last few years the driverless Paris Line 14 manages 85sec headways (real not theoretical).
With regard to the comments about ADO this was implemented some years ago. As was as I am aware auto-door close was not due to union reluctance.
In terms of opening the doors before the train stopped it was quite common on C Stock on the North side of the circle. As soon as the train came within range of the Right Side Door enable the doors started to open.
The problem with Brixton & probably Walthamstow is that the platform arrangements result in irregular departure intervals. In the parallel move a train can be entering a platform as the other is leaving. In the alternate cross over move one train has to be held while the other is using the cross over. The risk is that with the longer interval the second train will have longer dwell times as it picks up more customers – once it is late it will get later due to higher customer loadings. The plan at one time was to have regular headways was to hold the ‘early’ train at the next station or Pimlico to even out the headway. The contra argument was that artificial delays were not a good idea. Not sure what was implemented eventually.
Also one of the things that had to be done to achieve 30TPH was to have a new timetable system that would work in finer (1 sec ?) intervals.
For the history buffs I thought the District Line acheived 45 TPH at one time by having ‘sub-standard’ overlaps on the multiple approach signals and lots of track circuits.
Brizcommuter,
1) Similarly at Walthamstow Central with a pause added at Blackhorse Road to get the timings even for the rest of the journey. I didn’t want to go into timetable details as the article was already getting rather long. I probably should have added that the working timetable can be found here.
Also there are extra dwell times at various stations e.g. Tottenham Hale, Seven Sisters, for all trains. I presume this is because the round trip time has to be a multiple of the service frequency. This final constraint resulting in enforced added dwell times to all trains is one that no other line appears to have because elsewhere you can always “lose” an extra few seconds at a terminus.
Note also that I make it only 80 minutes running at 100 second intervals in the peak rather than the 90 minutes claimed by London Underground.
2) Thank you for the figures. I have suggested improving the dwell time because I suspect that is just about the only thing that can realistically be improved on at a terminus.
3) Happy to stand corrected on most frequent metros worldwide. The Ligne 14 frequency appears to be very recent (last year or so with the replacement stock that I was unaware of). Certainly, it never used to be anything near as frequent as that.
I think part of the reason it can be more frequent in Paris is a different attitude. If you get injured by the doors the general sentiment is that you have no-one to blame but yourself. If correct, it shows how culture plays an important part in determining maximum frequency.
Fascinating and informative as usual. But to ensure credit is allocated where due, I’m fairly sure that when I went to Chippenham to be briefed for an article on the new distance to go signalling for the Vic Line the company was still Westinghouse.
Pedantic of Purley 7 September 2017 at 10:44
said in response to QTR
‘3) Use the limits of material science to make the doors lighter but equally strong. This means you can open and close the doors faster. So maybe an extra second gained on both opening and closing giving 2 extra seconds.’
This was already being looked at for replacement doors for the Central Line to try to get over the ‘bunny hopping’ problem where the train accelerates the mass of the door causes it to compress the push-back spring and open the interlock thus cutting the motoring. The door then closes due to the deceleration and the interlock makes and if you are unlucky the cycle repeats. To get over this problem 2009TS & S-Stock were fitted with solid door locks. The intention of the ‘push back’ is to allow customers to self release if they are being dragged. As this was not possible on doors with positive locking sensitive edges were fitted to detect dragging. Unfortunately as well as detecting people being dragged along the platform they also detect coats and other thing that are trapped in the doors being pulled into the train – hence the well-known sensitive edge problems,
Achieving the scheduled TPH will become more challenging in winter when more people wear coats and the number of sensitive edge actuations increase due to HIBO (Heads in, Bottoms Out) as people bend over to miss the closing doors their coats stick out and get caught in the closing doors resulting in a sensitive edge actuation. Much more of a problem on Tube Stock as people standing by the doors bend over.
In terms of Platform Edge doors the mass of these is even more important than the train doors – you need to keep the energy ( 1/2 m v squared) below the level it will break bones if people are hit. Since the doors are higher and wider than train doors this is quite a challenge. Not helped by the manufacturers using one mechanism for two doors so you essentially get hit by the energy in a pair of doors – that reduces the speed and thus increases the time by root 2 (0.707) . There is an argument that you should have narrow lightweight metal platform doors with two actuators and wider train doors to make up for any stopping position errors.
There is an interesting comparison with the lift industry who use door pre-opening to reduce dwell times. They also have a lot lower maximum energy limit that trains and perhaps Platform Edge Doors.
Incidentally the way the Jubilee Line PEDs achieve similar closing times to the train is that they start closing when the door close audible warning starts while the train doors wait till the audible warning ends before starting closing. As a result they both close at about the same time even though the PEDs are wider and slower. This is difficult to observe for some reason but is quite clear if you video the door close sequence.
How long before departure boards count down to the nearest second? In Barcelona they already do this although they do have to jump backwards sometimes to compensate?
John B,
I can see if a blocked door causes a 10s cycle time, you’d end up with a 80/100s interval which would escalate with classic bus bunching problem
Yes, but unlike buses, the Victoria line is centrally controlled and doesn’t have traffic lights with sequences measured in minutes to cause a tiny delay to escalate into a bigger one.
With a centrally controlled system, if there is a small delay you can delay all the trains by the same amount (or marginally less) so you maintain headway. The Victoria line has the ability to coast trains if they are running early so delays can be made up to some extent by reducing coasting. A small delay shouldn’t cause the trains to bunch.
If someone delays a train by 10 seconds then you may have the whole line delayed by 10 seconds but as soon as the peak is over you have the opportunity to get back to time. That is the beauty of a network that doesn’t interface to anything else. If everything is a bit late it really doesn’t matter too much.
Dave Jones,
I personally think it is ridiculous to have next train indicator that gives time in minutes on a line that runs every 100 seconds. Others have told me it will be a lot of money to change it for very little benefit – as they see it.
I would argue that counting down every 15 seconds or 5 seconds (the timetable is graded in 5 second intervals) would make passengers aware of just how soon the next train will arrive and so let the current train go rather than delay it. Also it would help get people to develop the “every second counts” mentality.
I’ve given away my copy of the Penguin book of building the Victoria, but I seem to recall that the reason the platforms are too narrow and the exists can’t cope with the numbers is not the well-known use of schoolboys to model the flows, but that this was one of the first projects to be subjected to Treasury cost/benefit analysis. The BCR didn’t come out high enough for the mandarins, so costs were cut but chopping out the future-proofing over-capacity at stations,
John M
Sqrt(2) = 1.414 approx
[Clearly sqrt(2)/2 intended which is a number that appears all the time e.g. sin 45°. By the way that is why the Boeing 707 with 45° wings was so named. PoP]
Dave Jones
Err .. has anyone else here been reading Diamond Geezer’s saga of the Bow Road Train Indicators?
@Greg: I think you mean the “random train indicators”?
For the Victoria line where just about every train goes to the same destination and they are so frequent, is there really any point in having them? You could just replace them with a sign that says “Next train: XXX seconds”. Sod the destination…
As soon as one arrives it simply starts to countdown for the next one.
Greg, I was being a bit imprecise – the speed has to fall by 1 / sqrt 2 (0.707) to keep the energy the same thus the closing time .time increases by about sqrt(2) (1.414). In reality the time increase is not quite that large as the acceleration and braking rates for the door(s) can be kept the same but the top speed is lower.
PEDs also introduce a new problem – normally if your arm is hit by a closing door part the way through the stroke when the door is moving at greatest speed it will move sideways reducing the impact and thus the likelihood of broken arms.
If the train stops misaligned to the PEDs it is possible to get hit by the PED door moving in one direction at full speed and the (misaligned) train door moving at full speed in the opposite direction. This apparently happened to one of the testers in Paris and it resulted in their arm being broken.
Lifts don’t have that problem as they are always correctly aligned horizontally and there is only one actuator for the car and landing doors which is mounted on the lift car and mechanically couples to the landing doors when the car is at the landing.
Hope that clarifies things.
The point which may be missed by some readers, is that sqrt(2) is the unique (positive) number which is the double of its reciprocal. Maths-trained people manipulating expressions involving it tend to take this for granted, but sometimes the resulting arguments can be ever so slightly baffling to onlookers.
It is also the custom to try to keep surds out of denominators, so one automatically writes (the symbols denoting) “root two over two”, rather than “one over root two”, even though both mean exactly the same number.
Granted that a tube is not a bus. But it is still possible, even on a tube line, for the classic positive feedback loop to operate. Bigger gap between a particular pair of trains -> more people getting on the one after the gap -> longer dwell time for that train -> bigger gap still.
But measures to minimize this effect are indeed more possible on a train than on a bus route.
I wonder if a small tweak in railway law,or conditions of carriage might help with this issue?
Something along the lines of…In the event of loss or injury to a passenger,caused by their obstructing either the doors,or the departure of the train,the onus would be on the passenger to demonstrate gross negligence or malice on the part of the railway or its employees when seeking redress…..that would focus minds a bit.
@ Slugabed – and how many passengers have even a passing awareness of the Conditions of Carriage or Regulation of Railways Act? I’d argue very few so tweaking the rules in the expectation of changing passenger behaviour seems futile to me. Far better to emphasise through a normal “passenger behaviour” publicity campaign as are regularly done for things like not obstructing the doors, take care on escalators etc.
WW
I think it would take one high-profile court case to bring it to the attention of the travelling public.
It would also address some concerns which drivers have expressed here.
Re: GH – Having read Jerome K Jerome’s follow-up “Three Men On The Bummel” I can’t help wondering whether a cultural point around punctuality, orderliness and authority may have helped in Berlin, at that time at least. Maybe with the assistance of plentiful uniformed staff. (Possibly applicable in Moscow too, the latter point at least was demonstrated to a family member visiting ex-Soviet states accompanied by a member of the Salvation Army.)
@Balthazar – I agree very much with the cultural point. One might also cite the Swiss and Japanese approach to discipline. I well remember colleagues returning from a study visit to JR and reporting with “awe” that the drivers saluted each signal as they passed it; passengers were similarly disciplined . [Mind you, I suspect the Swiss take this too far – I recall toiling up one mountain to be confronted by a nice laminated and aluminium sign describing in minute detail the regulations for picking mushrooms, including the requirement to take one’s haul to the communal weighing point – no doubt followed to the letter. The threat of the Pflanzenschutzpolizei was omnipresent…]
As to the Moscow “close up and go” practice, I’ve always assumed that the determining factor there was fear.
There has been a recent change of how regular passengers behave on the Victoria: now that people are accustomed to there being a train immediately behind it discourages jumping in at the last moment.
TFB, TFO……..Your comment takes us back to the start of the Article as discouraging jumping on at the last minute and holding the doors was a consistent objective of his. Personally, I don’t mess with the Victoria Line doors on the current trains, not just because the trains are so frequent but because the doors bite!
Re 130,
” but because the doors bite!” Try the Moscow doors or ticket gates for real bite.
Why do they spend a lot of money to get 36tph and then instruct the staff that they must regularly destroy it all just because there is a ‘passenger ill on a train’?
[Apart from ‘to cover our backs and never mind what happens to the many thousands of other people, any of whom might have some medical problem that could go wrong through being subjected to the resulting gross overcrowding in hot weather [or whatever]]………….
Peter Kay – it used to be joked that the railway would run perfectly well if it were not for the passengers. Joked; as in, staff understood why it was a humorously disingenuous observation.
GrahamH
I recall reading an article (it may even have been on here) about all the pointing and saluting the staff do on Japanese public transport towards signals and whatnot. Conductors on the NYC Subway do the same to a lesser degree pointing to some sign above the platform before opening the doors.
It is part of their safety system / culture – salute the signal because you saw it, point at the mark because it means all of the carriages are actually on the platform so safe to open the doors.
Graham H ad Brightonreader
In Japan JR operating staff, as well as on the myriad of independent and municipal railways, salute each other as well as use point-and-say.
A salute is used between staff to indicate interactive recognition. When a driver signs on and receives his/her running card they will salute the supervisor to indicate that they have received and understood their instructions. The salute is returned by the supervisor. When there is a change of drivers en route they will salute each other as a recognition that responsibility for the train has been passed from one to another. At a station call the platform supervisor will salute the guard as a train departs to indicate that responsibility has been safely passed back to the train.
Point-and-say is used to carry out operating tasks. For example, for a driver each signal will be pointed to and called out as part of their safety culture. It avoids the situation of things being done on autopilot and vital but minute things being missed.
For the vast majority of Japanese railways the staff will do all of this whilst in full uniform and wearing white gloves so giving the appearance of military precision. Locals, who are used to such things, take no notice.
It’s interesting that the Munich S Bahn has been mentioned in the comments as a contender. Although several core stations have dedicated boarding and alighting platforms, the dwells are not noticeably shorter than what we’re used to here (takes a moment or two for driver to check two sides of the train, and the boarding platforms are crowded with people waiting for multiple destinations). They don’t appear to be able to squeeze much beyond a 2-minute headway and are moving forward by building a second core tunnel altogether.
A few observations re: Moscow
1) As far as I am aware, on several lines 40tph is considered standard during peak hours.
2) There are several infrastructure reasons why this is possible:
– Platforms are (generally) much wider, meaning there is much more capacity and platforms can clear quickly (or at least the platform edges, before the next train arrives).
-Dwell times are short, at all but the busiest stations they can be as little as 20s, or even less at quieter stations.
-Trains accelerate and brake significantly more aggressively than in the UK. Passengers learn very quickly to either stand properly or hold on.
-Trains are full sized, and with the slightly wider russian track guage, meaning you can comfortably fit two rows of people standing in the carriages.
– Trains have 4 wide doors per carriage.
-At termini, six sidings are standard. Trains approach the platforms at full speed, then continue into the sidings, before returning to the other platform. Over -carrying is not considered as much of an issue. Stepping back is also used.
-Platforms are almost always straight and level with the trains, reducing PTI problems significantly.
– There are very few branches , meaning no difficulties with interworking.
-Various signalling trickery that I don’t know the details of, allowing very short headways.
3) There are also cultural factors at play
– Obstructing the doors is heavily frowned upon, and likely very painful, meaning it is less common.
-Running for a train is rare, because there is normally one right behind.
– There is a culture of personal responsibility. If you disrupt the train, and get injured in the process, it is your own fault. Another example of this is how escalators generally run at 0.75ms^-1 rather than the 0.5ms^-1 common in the tube.
-Particularly in the peaks, passengers are disciplined in allowing alighting passengers off before boarding. If they don’t , then they will be ruthlessly shoved out of the way without a second thought.
A bit of an aside concerning the mention in the article of the Bakerloo terminus at Elephant & Castle (E&C). While pondering on why it terminated there, remember that the transport environment was quite different to that nowadays. The line was opened in 1906. The Charing Cross branch of today’s Northern Line came eight years later, but the City and South London Railway was alive and well and also serving E&C. Providing a tube route from south London to the West End made a lot of sense. Additionally, that forgotten transport mode, the tram, was very much alive and prospering in south London and E&C was a very important node. With no trams allowed in the West End, there was a strong likelihood of capturing a large no. of interchange passengers at E&C.
Although the trams would soon be crowding along Victoria Embankment, giving convenient interchange to the Bakerloo at today’s Embankment station, this was very uncertain when the Bakerloo route was being planned, and did not happen until after the Bakerloo was opened.
@ Fandroid: ‘…that forgotten transport mode, the tram, was very much alive and prospering in south London and E&C was a very important node’ reminded me of this long-forgotten gem: https://www.youtube.com/watch?v=rc9gtJndKE4.
PoP:
Background on how the Boeing 707 was named: http://www.airliners.net/forum/viewtopic.php?t=300151
Sin 45 is a coincidence.
@ DM1 – an interesting list of factors around 40tph in Moscow. Thanks for sharing. There are times when ruthlessly shoving people blocking doors is something I’d love to have been able to do. 😉 Quite why people imagine I can walk right through them has always been a mystery. ;-P
Re: GH – fear of the doors or of the men in uniform (or not in uniform, perhaps)?
Re: DM1 – many of the factors need to be designed in prior to construction, of course.
I’m no expert at all, but it seems to me that trains run a lot quicker now that the platform staff (who now broadcast themselves) set the train off before it’s completely full. In the 1990s, the train wouldn’t leave until it was physically impossible to get anyone else in. As a recent poster said, the passengers are happy with this as there’s another one along very soon.
Most people I know think the Victoria is the best line. The experiment with green shading areas to keep people out of the way of alighting passengers at King’s Cross St Pancras seems to be working well.
I am surprised that Moscow manages to ‘accelerate and brake significantly more aggressively than in the UK’. The acceleration rates and particually the braking rates on the Victoria are very close to the adhesion limits for dry steel wheels on dry steel rails. A bit more could have been gained by providing motors in the trailer cars but I beleive that would have exceeded the power supply current limit and would have cost more.
Of course with regen having trailer cars friction braking reduces the returned energy and means the trailer car wheels need more frequent turning to remove ‘hollow’ treads. The PPP evaluation formula did not recognise this and hence 2009TS has two trailer cars – lower initial costs but higher long term costs. Converting them to motor cars was looked at but is not easy due to the equipment (such as compressors) under the trailer cars.
Moscow acceleration and deceleration rates are generally claimed to be objectively higher. But any difference is subjectively magnified by the difference in jerk (or so my limited experience tells me, anyway). The key fall-over moments for standing passengers are at the beginning and end of the acc/dec phases. The v-t curves seem to have extremely sharp bends.
“50 years ago the Bakerloo line was the busiest Tube in central London”
Was this measured by crowding levels (passengers per sq m) or annual demand? Incredible to think as I think now Bakerloo is one of least crowded lines in Central London
Maybe not so incredible, as it has been effectively duplicated (by the Jubilee Line), as the article says, and the Jub has a rather more in-demand southeastern terminal.
If the new line had inherited the “Bakerloo” name (to which it would have been perfectly entitled), then rather less “decline” would have been perceived.
Martin (8th September)
You are undoubtedly correct in that a lot of the narrow passages and the restricted width of the platform was down to the government not willing to future-proof the line. However a lot of the documents from IMechE and elsewhere that Graham Feakins helpfully provided a few years ago (and other stuff published as recently as the Brixton opening) made it quite clear that the line, as built, should have been able to handle 30tph.
The question then arises as to why it could not achieve 30tph. Undoubtedly the signalling system let it down but part of the failure seems to be that dwell time was larger than desirable at critical places and this was not down to the width of the platform but the lack of free flow of moment for boarding and alighting. Given the innovation elsewhere it seems surprising that they didn’t pick up on how critical this was.
To take a simple example, they could have speeded boarding and alighting time by making the platforms slightly higher so that they were level with train floor. This would not have cost a lot of money at the time of construction . Their failure to do so seems to suggest they hadn’t grasped how critical it was and I would suggest this was down to using fit able-bodied schoolboys. I would also suggest that a test only involving schoolboys does not pick up on the social niceties of avoiding body contact which slows movement down.
Peter Kay,
I think you do London Underground and their staff an injustice when you refer to people ill on a train. Every reasonable effort is made to remove them but ultimately the staff do not want to be prosecuted for assault if the person will not move or cannot move and refuses to allow staff to move them.
In addition a portion of British Transport Police have been trained at London Underground’s expense to have sufficient medical expertise (and equipment) to be able to handle such situations.
Even if the person is entirely co-operative it might be the case that detrainment and moving the person to a place of safely takes a matter of minutes so the announcement is correctly made that the service is being delayed due to a person being taken ill on a train.
Fandroid,
Ironically, one of the many reasons for the City & South London Railway initially being a bit of a failure was the subsequent appearance of trams to take people to the City from places like Elephant & Castle. And using the method of traction that the City & South London helped pioneer! So, to that extent, it is a little bit surprising the Bakerloo went to Elephant & Castel. But, given the short distance involved and the fact that there was an above ground railway station there, probably well worth taking the risk on going there – but not worth the risk on going further.
Flare,
The Bakerloo was certainly the most frequent line in the 1960s – or at least one of them. It certainly felt as if it was the most crowded which I concede is not the same as saying its trains carried the greatest number of people. Other lines may have been busier in one direction by some measure but in Central London the Bakerloo was packed between Baker St and Waterloo. In fact it was probably packed to capacity between Paddington/Finchley Road and Waterloo.
Malcolm,
I suspect you are referring to the fact that the Jubilee line service both Baker St and Waterloo so could legitimately be the Baker St and Waterloo Railway – or Bakerloo line. However the Jubilee line stage 1 did not serve Waterloo so that is really stretching a point.
If the new line (today’s Jubilee) had inherited the original name (Bakerloo) that would have produced a situation where none of the original line was part of the new line except, probably, one platform at Baker Street.
PoP: good point about stage 1. But my main argument was really that, as you originally said in the article, the NW-SE corridor through central London (previously served only by the Bakerloo) now has both lines to take its traffic. But of course, we are really discussing the Victoria line anyway…
JohnM
I believe the 2009 Stock has a maximum acceleration of 1.3ms^-2 and deceleration of 1.14 ms^-2. The numbers I have found for Moscow Metro trains appears to be similar. Some newer rolling stock (for example the Yauza) appears to also be able to decelerate at 1.3ms^-2 in service.
It may be that on the Victoria Line with the recent timetables the acceleration rate is less of a factor (I am not a regular user). However it may also have something to do with driving styles. Moscow metro trains can and do enter and leave stations at speed (which I think may nowadays also be true on the Victoria).
This article (in Russian) gives a lot of analysis of the theoretical maximum throughput of a (Russian) metro system, both from a passenger capacity perspective and from an infrastructure perspective.
For one, it lists the average acceleration of a certain type of stock as 0.98ms^-2 and the deceleration as 1.28ms^-2 suggesting these maximum service ratings are regularly achieved.
It also talks about the importance of 5s padding in the timetable between stations to allow any short delays to be caught up in the peaks.
The theoretical maximum throughput it gives for two types of stock are 47tph and 43tph for the 81.717/714 and the Yauza respectively. It suggests that during delays in the peak, this throughput (although for brief intervals) is achieved, and that in general the metro operates at over 90% of this theoretical maximum.
In terms of passenger capacity, it suggests that for the 160m trains used, a line can consistently transport 83, 000 passengers an hour in each direction, with a 15 minute peak burst of up to 112, 000 passengers an hour.
Also notable, is that for the moment all lines are still manually driven, albeit with strict train protection and speed limiter systems (there is some experimentation with a domestically developed ATO type system,, currently with 4 trains on the circle line).
Re DM1 and John M,
I’m on hols at the moment so I don’t have access to all my useful data…
1. MetroWagonMash (the manufacturers) have confused public data that routinely mixes up 1.1 and 1.3ms^-2 for acceleration and deceleration numbers.
2. Moscow metro max speed is 90kmh / 25ms^-1 / 56mph so the gearing can be bit more advantageous that some UK tube stock at 100kmh (or even most NR commuter stock which is 121 or 161kph max)
3. Moscow using passenger densities of 10pax/m^2 for capacity modelling!
4. The installed power draw of some of the Moscow units is off the scale in UK terms – trains are effectively equivalent to a 8car commuter unit on Network Rail (Moscow untis are 8x20m cars with similar average car weight at 35-36tonnes) but with more power.
The newer Moscow units have a continuous rating of 5.45MW and the older ones 3.65MW on 3rd rail DC. A 12 car 700 is continuously rated for 5.0MW on AC and like all modern UK EMU is slugged on 3rd rail DC to prevent to much current draw (to arround 2.85MW) and the acceleration spec in the 700 contract is a minimum of 1.0ms^-2 on AC (ditto 345 acceleration rate).
So on a more even comparison, the latest 8car Moscow unit with 5.0MW vs 8 car 700 on AC at 3.3MW or a 7 car 345 (almost same length) at 3.6MW on AC is 50-65% more power and on DC as well…
Combined with gearing for a lower max speed, more appropriate wheel size than the 700s there is more than double the tractive effort from 0 to 25mph.
@ PoP – I’m slightly puzzled by your platform width comment. If platforms have insufficient width then surely this causes boarding and alighting problems. At some Vic Line stns it is nigh on impossible to alight from a peak train as there are so many people on the platform there’s nowhere to go. Clearly people push and shove and slowly move off but none of that helps dwell time especially without PEDs. It’s certainly not at every station but there are key points where platform capacity is completely inadequate even with a stonkingly frequent service. The congestion / crowding / dwell time management task at these locations must be very difficult indeed. As has been mentioned many times before there are also clearance issues in that people are not clear of platforms / adits / lower circulating areas before the next train arrives with the next slug of people. That’s usually down to inadequate vertical circulation to reach exits / interchange levels. This is why I “bang on about” LU needing more investment in station capacity.
I’m not party to official information, but I’m sure that the acceleration and deceleration of the ’09 stock was modified to be softer on the very start and stop after coming into service. When the trains were first introduced I found the final transition to the stop very hard and uncomfortable. I don’t think it’s a matter of having got used to it, as one continues to travel on other stocks and can compare. I wonder whether they improved it for passenger comfort or to limit the stresses on the trains too, and whether calculations were made on the overall effect on running times.
On staff being careful not to force-remove people taken ill, many years ago I saw the inexplicable survival of a one-under, who, after being helped back up onto the platform – considerably worse for wear – insisted that he didn’t need an ambulance, just a sit down and a cigarette! The staff dealt with it really well.
@ Ngh – in my simple terms you’re basically saying a Moscow Metro EMU is the Ferrari / GP car of the railway world whereas a NR spec commuter EMU or the an 09 stock are a fairly low spec sports saloon like a BMW 5 series with a diesel engine and no sports tuning? The Moscow Metro trains seem astounding in terms of their spec.
Having watched some clips on Youtube some of the stock does have incredible acceleration. Also older cars have wing mirrors at the front and back – presumably to assist with train dispatch / PTI check. Rush hour boarding and alighting in Moscow is something to behold – definitely aligns with DM1’s description. Multi layered winter clothing doesn’t help either!
Re WW,
The stampede for the escalators is also something to behold (the step on to the moving escalator is the limiting factor due to the higher escalator velocity)
Train spec – a good analogy. I’m not sure how efficient they are I suspect you could get the same performance with less power. Only the most recent have AC VVFD technology (from Hitachi) where as all the older ones are traditional DC motor control.
Re NICKBXN
The jerk (ms^-3) is software controllable on modern EMU stock so an easy modification. On braking the regenerative /rheostatic braking does the work of taking the train from normal line speed to around walking pace with friction braking then cutting in to do most of the final bit hence the blending in of the friction brake will also have needed software tweaks.
[The later bit is easier if the rolling stock manufacturer as access to the full code for drive operation so will be easier for Alstom, Bombardier-Siemens (as it will probably be from later today) and Hitachi. I think ABB are reasonably generous with CAF on software code but not sure about the other drive manufacturers but Mitsubishi, Toshiba have been open to western manufacturers. In the dying days of Ansaldo-Breda they were buying the complete computer systems including hardware and racks form Bombardier to try to improve the trains quality/reliability issues. Siemens have’t be generous on 3rd party software access either previously.]
Needless to say this option isn’t available on the older Moscow Stock (or easy to do on the newer stock)
Walthamstow Writer,
I’m slightly puzzled by your platform width comment. If platforms have insufficient width then surely this causes boarding and alighting problems
I didn’t say that – or didn’t mean to say that. What I thought I said was that the Victoria line was supposedly designed for 30tph and the passageways and platforms were probably designed to be wide enough for that. Otherwise why claim that it was designed for 30tph.
In my experience of Victoria northbound over the years, it is not the platform width that has actually made boarding and alighting difficult. It is the sheer number of people wanting to get off and a similar large number of people wishing to board. I can assure you that people managed to get all the way down the platform with the crowds. It wasn’t pleasant but it was possible and it was done.
I also am familiar with London Bridge westbound on the Jubilee line which is also very busy. It has really nice wide platforms but the problems are practically identical to Victoria northbound. Yet the width of the platform is huge and it also has a separate circulating area. It assists with movement within the station and makes the whole thing more pleasant but has little effect in improving boarding and alighting times
@WW, ngh et al
In aerospace the predominant Soviet, and now Russian, design philosophy is ‘lots of power’, compared to Western aircraft and rockets. Whilst effective, the fuel consumption was also considerably higher. Another aspect of this was that Soviet military aircraft engines also did not last as long as comparable Western ones. Whether this had to do with having higher power, or a wish to forego engine maintenance and more simply replace the engines more frequently, is not apparent. Furthermore, to bring this back to ground, it is not known if Soviet/Russian metro motors also lasted/last as long as comparable Western ones, and if maintenance is less but replacement more frequent. Not the kind of information officially published when export orders were frequent.
@ PoP – the obvious comment to make is that the original planning assumption seems a little odd. Designing a station for a theoretical train throughput is an odd way of framing things but I accept it may have been the “logic” used in the 50s/60s. Nowadays things are designed for specific demand levels plus a defined growth “margin” in terms of spatial handling. The assets, of course, are designed for the expected life cycle. The issue on the Vic Line, and a lot of the Tube network, is that peak and off peak demand levels are way in excess of what the stations and trains can comfortably handle. Isn’t the Vic Line recognised as carrying more than 3 times its originally planned annual demand level (100m+ vs 30m or so)?
I am very familiar with Victoria having commuted through there for years. I agree it “coped” but only on the margin and only because vast numbers of people were held back at gatelines or outside the station. While no one expects the peak in London to be “bliss” there really should be some thinking done about what is “acceptable” in terms of waiting conditions and time to move through the station to reach an exit or interchange platform, Some of what goes on here (and elsewhere in the world) is pretty awful if you have to tolerate it every day. Flitting back to Moscow again I certainly couldn’t cope with the peak hour crush I saw on some Youtube videos – simply horrendous.
Walthamstow Writer,
Pretty much agree with all that. My slight concern is there seems to be a belief held by some that if the station is crowded then expanding the station will necessarily mean more passengers can board or alight the train.
It seems obvious to me but if A is the problem then fixing B is not the solution.
In the early days we got claims that Victoria Station Upgrade will increase capacity. I really don’t believe it does anything of the sort. It was worth doing but for other reasons. It cuts door-to-door journey time though – substantially for some people. It increases safety especially if the station needs to be evacuated. It makes the station less unpleasant. It makes the single escalator down to Victoria line platforms less critical and it improves access by adding lifts. But I can’t see how it adds capacity – except possibly very slightly in the first two carriages.
What does seem to have made a difference is the increase in frequency. Also, as someone else pointed out, people are happier to let the first train go so dwell time goes down and the whole thing works a bit better.
LBM – from what I saw of Soviet “legacy” engineering in Eastern Europe, concepts such as wholelife costing and optimising useage never crossed their minds. The Swiss approach of repair and repair until the basic structure collapsed would have seemed wholly alien to them. The Philosophy was “Build it and then thrash it – and then buy another one” epitomised by the sight of a Russian coach driver in Stockholm trying to restart a recalcitrant engine by beating it with a crowbar…
Re: GH – a.k.a. “running the railways in a Bolshevik manner” as practised with predictable results in the ’20s and ’30s I believe. It is my understanding that part if the “lots of power” philosophy arose simply from technology that was less sophisticated than western equivalents meaning that there was simply more mass to be shifted for a given requirement. It made Soviet aircraft, spacecraft etc. highly impressive but didn’t mean they were better.
My experience of Soviet motorcycle technology (including the electrics (NOT “electronics,we are talking purely electro-mechanical here) was that their production was primitive, crude (built to broad tolerances, from substandard materials using very basic production techniques) but enormously strong and remarkably forgiving of ill-treatment.
As Balthazar says, this led to them being impressive on paper in terms of output, but “in the flesh” less than scintillating as the weight and lack of fine-tuning worked against them. Perhaps this was a pervasive philosophy in the USSR?
A minority pursuit, but still, apparently sought-after, those Soviet 4-strokes.
(A side-aspect of these particular machines is that they were the crude descendants of the products of reparated German factories,re-erected in the USSR post-war.
@Balthazar – There may be a lot in that. May be I’m oversimplifying matters (sweeping generalisation follows) but it has always struck me that the Russian approach was essentially a peasant one -build the largest machine you can to do the job,run it into the ground, and assume that another one will follow. Value engineering it ain’t.
Re Slugabed,
“was that their production was primitive,crude (built to broad tolerances,from substandard materials using very basic production techniques) but enormously strong and remarkably forgiving of ill-treatment.”
Agreed and applies to far more than motorbikes.
Re Graham H and Balthazar,
“running the railways in a Bolshevik manner” as practised with predictable results in the ’20s and ’30s I believe.”
Reminds me of a particularly horrific Mech finals paper, there was complete silence (you could have heard a pin drop in large room) as the
victimsstudents read the first couple of pages of questions which were pretty much unanswerable as regards getting a useful number of marks but some would have to be attempted so it was case of looking at least worst options. Then the first person who turned over to the last page of the booklet burst out laughing as the questions on the back page were even less answerable, there should normally have been a difficult but predictable fatigue question (among others) instead at the top of the last page was a different style of question including fatigue (RCF etc.) but based on a quote from Dr Zhivago asking the candidates to discuss the influence of Russian rail manufacture, operations, repair and maintenance on the plot of Dr Zhivago.Needless to say rail engineering wasn’t directly taught and the average engineering students knowledge of mid 20th century literature was predictably bad.
Rumours that the chief examiner for that year who also happened to set that question, wanted to make sure he never had to be an examiner again were never proved…
Everything commenters have said about Soviet engineering may be true but there is also the question of the high quality of engineering design, which took the constraints of Soviet production capabilities into account.
As an example, I give you the YAK-3, supposedly superior to other WWII fighter aircraft.
@ PoP – I understand your basic point of logic about what the capacity constraint is and what fixes what. Your other points re evacuation etc are all highly pertinent. I would just say that more capacious concourses, better vertical movement capacity and wider platforms give everyone an “easier” experience in terms of managing the station and passing through it. I’d also argue that at very busy locations having more space to actually get off trains and get out of the way quickly without creating pinchpoints will help dwell times, reduce conflict etc. Similar benefits apply to have space for people to wait safely, ideally in a line and clear of the doors.
You cited the JLE stations and while these vary somewhere like Canary Wharf has lots of space and works very well despite the vast numbers using the place. Obviously you can’t build stns on that scale everywhere but the very busiest places really should have that expansive provision. I await seeing the platforms on Crossrail deep level stations to see just how deep the platforms are to allow for people to wait, circulate and to exit platforms quickly and efficiently.
I also tend to look at railways as systems hence why I’d look at the train throughput *and* the station effectiveness. Obviously your article is about the train capacity so I am “pulling at the edges” of the line capacity debate. I can never consider somewhere like Finsbury Park in the AM peak as anything close to being “effective”. People 5 deep all along the platforms, jammed in cross passages and up stairs to the street level corridors is frankly rubbish and unacceptable whether you have 36tph or not. Anyway we’re broadly agreed so perhaps time for me to “shut up”.
@GRAHAM H:
“…the flow of bad language at design stage because of the difficulty of fitting everything in (especially the links to the District from the Victoria) was entertaining (and matched only by my own weaker efforts in relation to mopping up after a bodged French attempt to design a tramway for Vilnius)”.
That is a tale that needs telling! (and also my all-time favourite throwaway line in a comment on LR)
New Civil Engneer Article on this very subject …..
The basic nature of the original control system could explain what I witnessed once at King’s Cross St Pancras while waiting for a southbound Victoria line train. The approaching train didn’t seem to be slowing down as it usually did – as a result it barreled through the station at speed, followed by a screech of the brakes – I assume applied by the driver. As the dust settled it was clear that all but the last half carriage of the train had continued into the tunnel towards Euston. After a bit of faffing by the platform staff and the train operator it was announced that the train would continue on to Euston rather than attempt any kind of reverse manoeuvre or let passengers off the last half carriage..
@ Jon B – that used to be a favoured game of mine with the 67 stock – “is the train going too fast to be able to stop at the usual place?”. I could usually tell if a train was approaching too quickly and would thus not stop in the correct position. Sometimes it was bad, as in your example, and meant the train had to carry on. Reversing on the Vic Line with pax on board was rarely contemplated. Of course we often had the opposite which is that trains stopped too early and drivers had to quickly go into manual to drip the train forward to the right stopping point. Most drivers were extremely adept at this manoeuvre meaning little loss of dwell time. Can’t recall anything similar with the 09 stock but the overall system is now much more sophisticated.
And I am sure that 100andthirty will point out if I don’t …
This really was the Achilles Heel of the Victoria line in 67 stock days and went to show why, at the time, you really couldn’t fully trust automation. And remember they couldn’t even manage to stop a train at the correct location in a dry underground tunnel.
The sad thing was that in the final few years of 1967 stock, on their third attempt, they finally fixed this problem and the train worked as designed. Piers Connor in his writings has covered the issue of stopping the trains correctly on the Victoria line in quite some detail.
Something that got cut out from the article as it was getting rather long was the contrast been the crude electronics and computing power of the 1960s when the line was built.
The Victoria line was opened as far as Victoria in 1969 in the same year as the moon landings. The computing power in the average person’s mobile phone probably exceeds the entire computing power of all of NASA at the time of the moon landings.
Small wonder then that the trains couldn’t always stop in the right place and it makes it all the more of an achievement that they managed ATO at all.
@PoP: Notepad on Windows 3.11 was larger than the code used to fly to the moon and back. Apparently the computer needed to have the next program loaded at various stages during the mission.
I’m not sure if this is an urban myth, but it makes for good reading!
The link below is to a Geoff Marshall video on YouTube in which he waits in Pimlico between 08:30 and 09:30 observing the time between each train arriving. The shortest time is 79 seconds. He has a link to this article in the description.
https://www.youtube.com/watch?v=c8QKPgRa7sM
PoP….You mention computing power in the context of the original Victoria line ATO. No computers troubled the line originally. The electronics on the trains was made of logic modules which were made out of discrete components. The first LU on-trains integrated circuits were on the 1973 tube stock, and the first microprocessors were on the D stock. The 2nd generation autodriver box on the 1967 tube stock had a microprocessor. I don’t recall which one, but know it wasn’t mainstream and spares were unobtainable by the end of the century and necessitating the third generation of aurodriver box that took the opportunity to bypass the braking retarders – which I described near the beginning of these comments!
The increased frequency on the Victoria has certainly changed my own travelling behaviour. In my regular journeys to Walthamstow from Waterloo I used to use the Bakerloo to Oxford Circus and change to the Victoria there. Then, after the upgrade while travelling in the southerly direction, I found the sluggish and less frequent Bakerloo at Oxford Circus to be a source of personal frustration. I then started using the Jubilee, changing at Green Park. There might be a significant extra distance and elevation change by doing that, but at least it feels as if I am still moving fast for the whole journey! Bakerloo Line trains crawl into the Oxford Circus platforms, in a quite dramatic contrast to their neighbours on the adjacent platforms.
Fandroid. Three factors at play here:
1) At Oxford Circus, Victoria Line platforms and approaches are more or less straight. The SB approach on the Bakerloo is quite severely curved limiting the approach speed
2) ATO will always deliver the best braking performance – as good as, if not better than the best driver
3) The Victoria line brakes at an average rate that is equal to the Bakerloo line’s maximum service braking rate
Just to follow up on the comments about the computers used on the Lunar Landings, the computers on the command module and lunar landers were tiny and did have to have programs loaded in during various parts of the mission because they weren’t big enough to hold all the code. Nevertheless, this wasn’t a reflection on 1960s computing, but a specific design choice.
Firstly, the design was locked down by the mid-60s so were not state of the art by the time of the landings. They also had to be highly robust to handle the rigours of spaceflight, but the biggest constraint was weight – every kilo of weight carried to the moon (and back), required several thousand kilos of fuel at liftoff, so the computers had to be as light as possible and as low power as possible because batteries were extra weight. This meant the design was deliberately dumbed down to keep within a tiny weight allowance. The computers on the ground were highly sophisticated (for the day) but weighed tons.
The 1967 tube stock would have had some limitations on weight and volume which would have affected the capabilities, but not nearly as severe.
Thanks for the interesting article. (You may wish to correct the spelling of Piers Connor’s name.)
[Done. I get irritated when people misspell names so pretty unforgiveable. PoP]
What I think is critical in the success of the VL Upgrade is reducing the average loading of the carriages.
It seems to me that, in general, once a carriage has reached a certain level of crowding (which I will call ‘full’) it gets progressively and very quickly more difficult for those behind to get on. This factor increases station dwell times beyond that which is desirable and for many years a certain amount of this had to be tolerated because passengers would not let a train go; even if they did they would simply contribute to the overcrowding of the next one. Obviously, on any train the effect depended on what was happening on the slowest car.
By observation, what I find now on the Victoria Line is that the extra trains mean the cars load below their ‘full’ limit so that everyone can get on quickly without having to squeeze in such as to cause a delay. This is surely a far more profound a change than the thought in a passenger’s mind that “there’s another one behind”, though that will help. This is all very much a human factors thing, about how people on trains move down and how much pushing and shoving you think those already on the train will tolerate! Unfortunately, it means that in a few years’ time, when traffic levels have shot up yet more, the new trains and 36tph service will become ‘full’ again and I fear at that point boarding times might increase alarmingly.
Technical papers during the 1970s suggest that the desire of London Transport was to schedule trains to meet about 75% of crush load and this feels about right for easy boarding and may well be what the loading is now. If more people attempt to travel than this, there will be a problem. When I was on the Victoria Line, I fear certain sections were loaded to 90% of crush load, maybe more. It is surely this difference between ‘full’ and ‘crush loaded’ that rapidly creates these intolerable systematic boarding delays of which, at the moment, we are relatively free. The circle is virtuous because travel is thus quicker and more pleasant.
As Pedantic of Purley and others have noted, the main constraint for the Victoria Line classic train service was the signalling (and to a lesser extent maybe the track layout). Having just checked, the Victoria Line trains were ordered as manually-driven trains in 1964 with the facility (and hope) that ATO would be approved sufficiently quickly for the equipment additions and alterations to be accommodated before fitting out began (which is what happened). This put great pressure on the ATO design programme and I suspect both shortage of time and money played a part in designing a system to cope only with what was essential and without too much excess capability. The Estimates for the Victoria Line in 1958 had been for 263 million passenger miles a year and by 1967 this had dropped to 203 million, a drop of 23%, against a background of falling usage of public transport more generally. If this same factor were applied to an aspirational 30tph, which was talked about in the late 1950s, we arrive at a requirement for fewer than 24 trains an hour when ATO was being designed! In that light installing a signalling system probably able to hand 27-28 trains an hour might not seem so unreasonable. We might speculate about what we would have got had ATO not been approved. 30tph capability?
A contributor felt that more than 27 tph had been attempted in 1967 stock days, partly by ‘flighting’ a 2-minute service for short intervals. Indeed so, when trains were available in very late 1980s! However, my recollection is that after the peaks, even on good days, the service finished late by a few minutes (5-10 minutes or so perhaps). Since each two minutes of lateness represents a lost path the reality was that it was doubtful if adding more trains to the timetable actually achieved much. I hope I hadn’t given the impression that ramping the service up to its realistic maximum made it worse, for on a good day it was self-evidently not the case. My concern was about making it more fragile so that delays rippled faster, had more damaging consequences and took longer to rectify.
I write this with my own John Self ’90-second railway’ coaster in front of me! I don’t think 40-tph is impossible, but it leaves absolutely no room for delay, error or mishap of any kind on a line that is unforgiving.
@Mike Horne
If I have understood you correctly people do not try to squeeze into a full train (which is the most time consuming part of loading) because they have learnt to have faith that there really is another train right behind and that is unlikely to be completely full, meaning everyone gets to where they want to go faster. What a pity this faith did not extend to those who insisted in walking up the escalators at Holborn during the recent “stand on both sides” experiment.
Not quite. Someone else made that point. I was suggesting that because there are more trains each one is less busy (ie under my ‘full’ definition) so that people can board freely, Improved regularity has also helped. Under the old technology the lower frequency of trains (with similar capacity) became systematically over-full and significant numbers of people boarding later during the station stop (maybe 10% of all those boarding) boarded progressively more slowly causing excessive boarding time. I suggest from observation that by increasing (achieved) frequency by 27% or so, the carriages are no longer so full that boarding is significantly slowed down by those at the rear (I’m not really talking about the stragglers). There is a threshold, which I call ‘full’, under which people board freely and above which delays become increasingly unavoidable.
With my usual caveat of “small sample size”, given I use the tube rather less than I used to do, I’d also say that the simpler service pattern also helps. You no longer have people waiting for Walthamstow trains and letting Seven Sisters ones go. This will have the effect of smoothing the boarding pattern overall. In the past those wanting to go beyond Seven Sisters would wait and if an over “full” WW train came in there was even more desire to crush inside it than have to wait possibly another 4-5 minutes. This caused longer dwell times and, of course, it worsened as you headed north through Zone 1.
This may sound like slightly daft behaviour but a lot of people have onward connections to make from places like Tottenham Hale and even Blackhorse Road. People are not keen on missing trains which may mean up to a 30 minute wait at somewhere like T Hale in the peaks given the Greater Anglia skip stop service pattern. Even missing a GOBLIN train may mean the difference between getting on or not in the peaks given the chronic overcrowding at Blackhorse Road. A 4-5 min wait on the Vic Line could all too easily become 14-29 mins elsewhere..
I think one other small influence may be that the high and consistent frequency for many more hours coupled with faster run times may have helped to spread the peaks a little bit more than in the past. This may also contribute to easy loading and fewer over “full” trains.
Re: Mike Horne – “The circle is virtuous because travel is thus quicker and more pleasant.”
Surely in this case, as in road capacity increase, there’s no such thing as a virtuous circle since the predictable outcome is that more people are encouraged to use the system until it has reached the previous (hence demonstrably tolerable) level of congestion? As you point out in the same post.
Balthazar,
But surely the logic is that mobility is basically a good thing? It encourages people being better suited to the job as they are in as there is more choice, knowledge is spread around, leisure opportunities etc. etc.
In the case of roads this is offset by the disadvantage that, as demand rises, proportionally more space is needed for roads (and parking). Often this leads to the fabric of the city being more spread out and sprawling which in itself reduces mobility in the sense that things end up being further away and less accessible. This disadvantage are is not intrinsic to rail and certainly not to underground railways.
Whether you choose to accept this argument is another matter.
If one accepts Mike Horne’s argument, and I think there is a lot of truth in it, one could look at the problem a different way and design stations so that platforms can have the number of people on them limited to the number that can board quickly.
Not easy to implement retrospectively, I grant you. But perhaps there could be more cases of deliberately only having just one down escalator to act as a limiter to the number of people arriving on the platform.
@PEDANTIC OF PURLEY 15:04
We cannot design stations in a platform capacity model that you suggest as that would mean having a 50 year ahead view of how things need to be.
Surely the whole point is that at the time of design we have absolutely no idea how demand will be that far ahead. There will certainly be no desire to decide capital cost on useless demand forecasts in a hypothetical future.
Kit Green,
No, but you can design stations so there is a safe holding area and that access to the station can be prevented when platforms are so busy that boarding the train will be delayed. You could do that in many situations without having much of an idea as to future demand.
They had no real idea how busy North Greenwich would be yet crowding at that station is much easier to deal with than at a lot of other stations where no real consideration for it was made. Wembley Park is another excellent example although in that case the station was modified to be more appropriate for handling large crowds.
There are lots of places where people queue for their ride, and a vehicle’s worth of customers are admitted to a holding area so as to await arrival of their vehicle. This only works because the operators know that everyone is getting off when the vehicle arrives, thus allowing everyone in the holding area to get on; the getting off area is usually separate from the getting on area. The vehicles in question are cable cars, theme park rides and so on.
This couldn’t possible work on the tube as no one knows how many people will get off, The recent wifi tracking exercise might allow estimates to be made, but monitoring in real time is, I suspect, some time away.
You could achieve much better boarding with social engineering at minimal cost. I despair how people refuse to let others off the train first with a clear exit path, or won’t move away from the doors inside. There is far too much observing a crush with helping to alleviate it. But then London commuting is a selfish experience, as you are surrounded by strangers, unlike the bus home from the small town market.
Of course its easier to organise better signalling rather than better behaviour, but its not cheaper.
John B
Not so.
Most of the time, in most places, with the great majority of people, the commuters do know to stand to the sides & let people out & then flow in. Thus rendering all LUL’s “announcements” pointless …
BUT
Every so often you really notice;
The out-of-towners who haven’t a clue, or, as I saw on Tuesday @ Victoria on the Circle, some selfish b^^^^^d who simply didn’t care & pushed his way in.
But, the reason you notice it, is simply because it is so rare. I’ve noticed the same phenomenon on the Paris Metro, too.
John B
You should visit Canary Wharf and see the orderly queues which form at each set of doors in the evening rush hour. Presumably a result of it being 99% commuters who do the same journey every day rather than occasional users, and also knowing exactly where to stand – will be interesting to see if this develops at the central Crossrail stations when they open
100andthirty,
I am sure experienced control staff have a pretty good idea of the number of passengers that can board a particular train. Maybe not in absolute numbers but in terms of how many rows of passengers they expect to clear on a particular train. Even if you have too many people, if those that do not get on perceive that they can definitely get the next train and the crowds are not that great, you have achieved your objective.
One thing I don’t think people totally appreciate is the future impact of “big data”. Whether by Wi-Fi phone analysis or other counting methods you could have a pretty good idea of the number of people involved and, like weighing the contents of carriages, you can adjust the algorithms in the light of experience.
I suspect very few people have the slightest idea of the use of big data to get the information required to predict the time of the next bus. This is not anything as crude as just looking at where the bus is. The previous two weeks data is looked at to deliver a “best guess” based on time of day, day of week, how long it took the immediately previous buses etc. If they can do all that, predicting the number of people getting off at an underground station should be relatively easy. You even have the advantage you have tagged every almost every individual passenger with a unique number and know exactly when and where they enter the system and when and where they exit. Such information is already being used (admittedly not in real time) to auto-complete journey costs when the user failed to touch in or touch out.
I could give loads of examples but just look at see how closely supermarkets manage to match supply and demand on items such as ice cream and salad based on weather reports. Or how the National Grid is confident that in future it can predict supply and demand despite the expected increase in the number of commercial wind farms and both domestic and commercial solar farms.
Are your really telling me that London Underground can’t manage something that is, compared to other examples, relatively simple?
The queues at Canary Wharf are quite a phenomenon that never ceases to surprise me. I find it quite soul destroying to feel compelled join the end of a snake so far from the doors, and the lines make it difficult to move up the platforms to find better places to board. I don’t see these queues being any more efficient than a general bunching to each side of the doors, but it obviously works for the regulars. It happens at Canada Water and London Bridge to a lesser extent, but the narrower platforms there doesn’t encourage it. I can’t see it happening on Crossrail except at the Wharf (old habits…), due to a combination of ‘Tubular’ platforms in the central section and more mixed crowd. My prediction is that it will develop at Paddington and Whitechapel eastbound in the mornings, as a big proportion will be Wharfers, but the variety of destinations and Paddington terminators westbound in the evening will make it unlikely.
PoP.. this is an ‘over beer’ discussion. From my work with big data (no comments about old dogs, new tricks please!!! ) it is neither simple, nor something that will yield the results required; therè are so many variables. For example, the surplus capacity on the Victoria line at Euston will depend on the current performance of other trains arriving at Finsbury Pàrk, Highbury and Islington and Kings Cŕoss St Pancras. However, even if this could be done, there is nowhere to hold the passengers who can’t get on the first train. The latter was my main point.
100andthirty,
Yes, providing the physical space for this to work is not the sort of thing that is easy to do retrospectively.
Approaching Mike Horne’s comments from a different perspective, one of the characteristics of fluid dynamics is that flow increases with demand as long as the flow remains linear. As the demand approaches and exceeds the capacity the flow loses linearity and becomes turbulent and the flow reduces rapidly to far less than theoretical capacity. This applies to water in pipes, to cars on motorways and people on trains – if the demand exceeds capacity the flow becomes turbulent (too many people trying to get on increasing dwell times) and throughput reduces to far below theoretical capacity, which worsens the queues and makes the flow still more turbulent (a vicious circle indeed). So increasing the theoretical capacity (eg 30 to 36 tph) can increase actual throughput by far more than the implied % (ie by more than 20% in this example) if the effect is to remove the turbulence in the flow.
Munich: https://de.wikipedia.org/wiki/Stammstrecke_(S-Bahn_M%C3%BCnchen)#Betrieb has the Stammstrecke (central core) of the S-Bahn running at 30 tph as of 2007.
@ML – and presumably the effect is symmetrical, so as one approaches exceeding capacity there is a far faster loss of throughput?
Graham H
Yes.
When it “falls over” the transition is fairly sharp & the drop-off in capacity/throughput is similarly unpleasant.
See also “Stall” characteristics for an aircraft, which is (basically) the same set of conditions.
Calculating the Reynold’s number for the Victoria line would take a lot of the ‘enthusiasm’ out of ‘transport enthusiasm’! Still, no doubt there is an analogous quantity, of equal relevance.
@Ben – ah, the Reynolds number! In my misspent time as an undergraduate, there was a PhD project described in the University notices as “The movement of smoothwater craft in confined spaces when the Reynolds number is greater than X”; this became widely admired when it was realised that what the project was actually about was canal barges going up and down in locks – something which could presumably be done glass in hand from a suitable canalside pub.
I’d like to caution against heading too far in the direction of intuitively-appealing analogies between fluid flow and the flow of discrete, autonomous entities (e.g. people or vehicles). Continuous fluids can indeed be represented as discrete particles, and vice versa, and much early traffic flow and building evacuation modelling did just that. However, such assumptions only hold provided that the particles or continuum obey strict and homogeneous rules of behaviour. Independent preferences, autonomous decisions and unpredictable behaviour render such models inaccurate. For this reason, modern people and vehicle flow models and [I suspect Stewart meant to type ‘are’ here. LBM] not based on the same mathematics as fluid flow simulations but on instead constructed around behavioural profiles.
To give a simple example, the flow of people on the escalators at Victoria station could be modelled as a fluid with a good degree of accuracy because everyone on the up escalator wants to go up and everyone on the down escalator wants to go down: they are like fluid “particles” in a pipe. Contrarily, their complex interactions at the top and bottom of the escalators could not be modelled accurately as a fluid because each individual has their own preferences about where they want to go and so their behaviour can no longer be described in a continual form. In other words, it is precisely when the flow becomes “turbulent” that the analogy breaks down.
@Stewart – yes,modern passenger flow models such as Legion seem to have such perturbation factors built in. (Sometimes frivolous, I grant you, such as the inclusion of down and outs, or chuggers whom everyone tries to avoid).
@Graham H: We can only hope they also include: “Tourists with giant suitcases stopping at the top or bottom of escalators”
😉
@SHLR 🙂 Not to mention people with enormous backpacks swinging wildly round and the unprepared (such as the person who stood firmly in front of the open doors of the train that I was trying to board at Liverpool Street for Pinner who demanded to know how to get to Greenwich…)
A major factor in increasing train frequency is reducing dwell times.
I imagine frequency is going to be an issue on CR2. Dwell times would be reduced with simultaneous boarding and alighting, on opposite sides of the train. Three platforms at busy stations, a central island for alighting and side platforms for boarding. Total platform area and number of stairs etc. may not be very different, so a relatively cheap way of increasing capacity? Is this done anywhere? I’ve not seen it, what are the downsides?
@ RogerB 29 October 2017 at 17:54
>SNIPSNIP< Is this done anywhere?
Used to happen at the old Wood Lane station on the Central Line, IIRC.
Or even simply, doors opening on both sides, as presently seen at Barking on the eastbound District & Stratford on the westbound Central lines?
@RogerB – highly desirable but not cheap at all – think of the cost of slewing the track and enlarging the station footprint – and that’s just at the surface stations. Underground, effectively a whole new station specially bored not by TBM – £500m a pop including some very expensive adaptation works.
To be fair to RogerB, he did seem to be talking about Crossrail 2, where it might be possible to incorporate wider stations at this early planning stage?
@John UK – indeed, although that will rack up the cost of an already expensive scheme. (There’s an interesting – and unanalysed – issue as to whether if you have only a few stations – as you would – that are double sided – the punters would respond as planned.)
@RogerB
Munich S-Bahn has platforms either side of the train in the central underground section. One side is intended for alighting only. However, eastbound and westbound lines are vertically separated, rather like the Jubilee at Westminster.
@RogerB: Brussels has it at a few stations. The doors on the exit side always open first in order to make those unfamiliar with the system get off on the correct side.
Thanks for comments.
At busy stations we try to segregate flows by direction from ticket hall to platform. My question is: In principle, is it worth taking it one stage further and onto the train?
John, I was thinking the total platform width may not need to be any greater: same number of bodies and reduced conflict, therefore the overall station width may be the same?
Greg, although the doors open on both sides, as I recall it’s not a compulsory one way system so you don’t get the full benefit?
Graham, with on-board displays flashing up the direction of exit I would have thought the punters would soon catch on.
MoK; NICKBXN on 9 Sept talked about Munich. No indication of how much slower it would be without one way flows. Presumably their CBA suggested this was worth doing.
@ Roger B – given that the CR2 central area stations will all have interchange with other lines then it isn’t as straightforward as just controlling an exit flow from the alighting platform. You may need to cater for multiple flows off that platform with the same being needed to the boarding platforms. I’d also question whether you get any dwell time gain because if you delay the opening of the boarding doors to ensure people have alighted to the correct platform you may not gain anything. The train driver is tasked with having to manage 4 actions – door release and closure and for each platform face rather than 2 on a conventional platform.
I suspect there would have to be some very convincing numbers in terms of benefits *over a long time period* to justify the extra construction and ongoing maintenance costs – cleaning, lighting, staff presence, CCTV, platform edge doors etc. I wonder if there wouldn’t actually be more benefit from having an extra track and platform faces to allow trains to arrive into a station as the previous train was departing. I recognise there is a load of cost with this option but I believe this happens with the RER in Paris and it helps to keep dwell times down and headways tight even with ATO.
Munich definitely sees the two platform faces per train as an advantage worth paying for, since the 2nd core section is going to have them too. For a city of its size, it’s quite something, as it’s analogous to London building a 2nd Crossrail 1 just one block to the north within 50 years of the original one opening. It has taken a long time to muster the political will between the city and Bavaria state to fund it, and they are not cutting corners with the size of the station boxes.
As noted in my previous comment, from the experience of my time regularly commuting there, I’m not sure it does a great deal for reducing dwell times, but it certainly makes circulation on the platforms and through the stations more efficient (as noted by others, half of the battle) since it’s all one-way… well nearly all one-way: for those who get off on the wrong side to be faced with escalators all coming towards you, there are also fixed staircases to the rescue.
Expedients like two platform faces, or even two tracks in the station, serving the one line, are ways of pushing more passengers per hour through a single tunnel. The trouble is, once you have gone to that much expense building the extra platforms, passages, lifts and escalators that this requires, you are coming close to doubling the cost, what with stations costing so much more to build than plain line tunnels. If you can actually afford this nearly-double price, you might be better off building two complete new lines, rather than over-gilding one line.
Re: Munchen
From my visits in the dim and distant past, I think the separate boarding and alighting platforms did make a difference to the dwell time. Arriving at the station, the contents of the train (passengers) drifted towards the alighting side, forming a space for the boarding passengers to start filling as soon as their doors opened. This drift kept going until the doors closed. With no conflict at the doors, the timing certainly felt quicker.
Also, having the platforms the same way round throughout the middle made it much less of a worry that the press of people getting on at one stop would prevent you getting off at your stop – something that keeps people near the door on the underground (yes, I’ve been that person, with the suitcase, and the back-pack…)
@ NICKBXN – and the chances are, once one reaches street level in Munich, there’ll be something as modern as an all-electric tram outside or nearby to convey you to your final destination. Just saying.
Fascinating discussion.
Malcolm, isn’t the point that if you are having a one-way pedestrian system then separate arrival and departure platforms does not mean extra passages, lifts and escalators? They’re just in slightly different places. And if total platform width is determined by the total number of bodies the only additional cost of two platforms is the wall retaining the second platform?
RogerB: Yes but. If the reason you’re building these extra platforms is to make a more intensive service possible, and thus carry more passengers per hour, then the “total number of bodies” will be significantly greater. If you are only building them to carry the same number of passengers, then perhaps they will not cost much more, but there will be no extra revenue to pay for even a small amount of extra digging.
Madrid has a number of stations with an extra central platform, from memory alighting passengers use the central island and people waiting use the outside platforms. The doors open a few seconds earlier on the alighting side, so the space is already created for people boarding. This also minimises people getting off the wrong side, so as RogerB mentions you only need one direction of escalators/stairs
Won’t the arriving routes have much more surge traffic than the departing (and simultaneous arrivals from different directions would stress a central platform). You’d need to scale both routes by the peak flows morning and evening, rather than currently have a small counterflow in a single tunnel. Unless you had rigorous separation people would either take advantage of short-cuts or get muddled at the bottom of the wrong escalator.
I suspect these solutions work much better for liquids than people.
@JohnB – It depends.
Even with a ‘Ninety Second Railway’ the running tunnels are in use for less than 10% of the time, so even though they’re ‘relatively cheap’ (Malcolm) it would seem desirable to maximise their use. You wouldn’t build any other utility like this – putting a half inch tap on the end of a two inch pipe (John B). It seems Munich is working on it.
Rather than guess, there are some “scholarly” documents with equations by, for example Network Rail
http://bailey.persona-pi.com/Public-Inquiries/Trafford-Park/Core-Documents/B-Other-Documents/TfGM.B029.pdf
and a Swiss one (trains, not the font, in English)
https://infoscience.epfl.ch/record/217368/files/EPFL_TH6876.pdf
@RogerB – I assume you are writing ironically; perhaps you mean like the joke about the consultants’ report on musical instrument utilisation during a Mozart symphony.
FWW the absolute physical constraint on TPH on anything other than a single -track 00-style loop layout is the time taken to move a set of points and set the signalling accordingly – probably about 60 sec. Even that assumes a lot about station dwell time and the time taken to accelerate and deaccelerate without colliding with the train in front Most railways like to build in some safety margin on top of that. A similar principle applies to roads, too,of course, albeit with different metrics.
“Q: If one train can travel from A to B in twenty minutes how fast can five trains travel from A to B?”
@AlisonW – simples – 100 minutes, as in “I played all the right notes but not necessarily in the right order”.
@AlisonW: I guess that depends on how many drivers you have!
Here is the cross section of Munich Hauptbahnhof – they are not holding back. It’s similar to the existing S-Bahn station. It definitely makes for a bigger and more expensive station box, but evidently seen as well worth it. I’m intrigued as to how the expected footfall for each of the boxes compares with projections for Paddington or Liverpool Street Crossrail… which look more modest by comparison.
http://res.muenchen-p.de/.imaging/stk/responsive/image300/dms/aktuell-2017/verkehr/zweite-stammstrecke/zweite-stammstrecke-hbf/document/zweite-stammstrecke-hbf.jpg
Since the 2nd tunnel is designed to enable the existing 7-or-so lines to increase from 3 to 6 tph on the outer branch sections, both tunnels will be running at current 2.5-minute freequencies from the start.
The projected map looks even more like a circuit diagram than the current one – but that’s how you’ll get over 40tph through the key stations.
http://www.mvv-muenchen.de/fileadmin/media/Dateien/5_Aktuelles/dokumente/2017_04_mvvnetz_2026.pdf
All the’ll need to make it work is to have INAT to make the map easier to follow.
Thanks Nick
From the various comments above it seems to me that Munich have it about right, the ‘four platform’ station layout providing maximum practical utilisation of plain track tunnels and station space.
Coming back to my original question, is this being looked at on CR2 or would two platform stations (and about 50% utilisation of tunnels) be adequate for the foreseeable future?
@RogerB – the short answers to your questions are “no” – for the reasons stated: cost and the irrelevance of tunnel “utilisation” as a useful metric in the rail industry.
To expand slightly on Graham H’s answer, tunnel utilisation could perhaps be a useful metric in the context of an existing line where more or bigger tunnels have already been ruled out as too expensive (e.g. current and recent Thameslink improvements). But in the context of plans for a completely new line it’s not so helpful.
Which brings me back to an earlier point: double platforms might well be feasible for CR2, but the money required to build them would probably be better spent elsehow (e.g. kept for CR3, wherever and whatever that may be).
@Malcolm- a combination of tph and train capacity is always a better metric than simple utilisation because they enable one to make an analysis of the factors involved.If you were looking for a single measure,it would be PAX/hr. A percentage figure is irrelevant because it implies (as RogerB says quite explicitly) that failure to achieve 100% is a failure. For reasons you will know that flies in the face of physics. For those who think otherwise,I suggest they buy a circle of Hornby track,fill it with trains completely and then see what happens at stations..
It sounds to me that the debate about double platforms, while now being about money is in fact, as with so much about public transport in the UK, really down to the failure to invest in the 1960’s / early 70’s.
I well remember my first use of the cross city Munich S Bahn with my InterRail pass in 1974. It was a world away from anything in London. Now it’s almost impossible for cities like London to catch up.
Politicians have got to understand that sometimes spending money for which they will get no immediate benefit / electoral boost is worth it to future proof the place.
Graham H: You are absolutely right. I was only addressing the difference between applying a metric to an existing line and applying the same metric to a planned line. But for either situation, you correctly point out that a percentage will not do.
Having said that, it is clear that various things could be done for a future planned line to improve PAX/hr, if such an improvement is desired. Building CR2 with such extra extra capacity might turn out to be something which generations yet unborn might be very grateful. Or they might not. It’s hard enough to know what will be needed next year, so anticipating requirements for 2075 onwards is something of a mug’s game.
@ap 1 November 2017 at 13:52
It sounds to me that the debate about double platforms, while now being about money is in fact, as with so much about public transport in the UK, really down to the failure to invest in the 1960’s / early 70’s.
Hindsight isusually 20/20 vision!
In the late 1960s/early 1970s both British Railways (post Beeching report) and London Underground were not seen as having great futures: the car would be king.
I suspect anyone in 1970 who then presented today’s annual passenger journey numbers as a forward projection would have been laughed out of court. The men in white coats might even have been summoned . . .
@John U.K.: Funny isn’t it, that in those days across a mere little 30 mile ditch, metro systems were being built, tram networks expanded and high speed rail lines planned.
What a bunch of mugs they were!
@Malcolm/AP – if only. I wouldn’t seek to justify the failure to look forward far enough except to say that I have never, in half a century of struggling to find funds for publicly funded projects, ever been faced with there being more money available than we needed to meet the immediate needs – and that if we were lucky. The best that anyone can do in those circumstances is a bit of good by stealth – the ghost T5 on the loop at Heathrow, the very long runout on the second to-be-electrified route to Cambridge, and so on. Sometimes one misses an obvious trick or two – perhaps infilling the missing gaps on Redhill-Reading (although it’s quite difficult to conceal the necessary extra substations; maybe we should have bled the current off SWML at Farnborough). However, these are small examples; it’s really difficult to get away with double-size stations, for example.
@John U.K. 14.03
I agree hindsight is wonderful but ask yourself this. How come the Germans and the French both kept at it on public transport?
I’m sure they heard all the car is king messages, yet Paris is now going to find it easier removing diesel and petrol vehicles from its streets than London is.
Imagine if the London mayor was to announce a ban on all diesel cars from 2024. Already promised for Paris.
@AP: Perhaps they did two things:
a) Stand back and see that all those cars were only going to lead to one thing: gridlock!
b) Had a slightly more holistic view of the world and realised that not everyone could travel by car (e.g. too young or old) or wanted too!
The oil shock of 1973 should have put paid to the plans for “carmegeddon”, I’m surprised it didn’t here….
I think at least part of the reason why the French and Germans continued investment in public transport in the 60s, 70s and 80s is that there was still broad support for public sector investment and management of key infrastructure and operations. In contrast, in the UK since the 1970s there has been a sizeable part of the body politic which opposes any public sector operations on principle, on the belief that the private sector would always be more efficient and better. Because public transport was under almost complete public sector control until the 1980s, with railways under complete public sector control until the mid 1990s, these were, on this view, inefficient by definition and therefore not worth investing in. The willingness of all Governments to spend much, much more on railways since the privatisation programme just emphasises this point.
Quinlet – I agree with your remarks about the lack of political consensus. I think there is and continues to be a broad level of support in countries like France and Germany for public transport investment. Of course those countries have their own transport woes even if we think they are “perfect” on fleeting visits or holiday trips.
I suspect that the UK having access to North Sea oil didn’t help to make us less car dependent and we squandered those revenues on day to day spending rather than on investing for a future when the oil and gas had run out. If pressure to improve air quality grows substantially across the UK, rather than just in London and a few cities, then we will face an enormous crisis as to how to get people out of their cars. So many places have lost bus services and the roadside environment is not conducive for walking and cycling so modal switch will be very difficult. I refuse to believe that our electricity generation and distribution infrastructure can cope with mass charging of electric vehicles so we’re going to be a right old mess.
I fear that rational debate about the relative merits of different forms of transport was disturbed by the then Prime Minister and her slogan of the “Great Car Society” and her running attack dogs who dubbed buses as loser cruisers. This was the same PM who,at her first and only meeting with the BR Board remarked that if they weren’t a bunch of losers, they wouldn’t be there.
@WW
Yes, grid issues are a real problem both in terms of overall power supply and distribution issues. The business models don’t help, either. The sad story of UPS demonstrates the issue. They invested in a fleet of electric vans for last mile delivery in London only to find that the grid told them that they would need a new substation to allow charging at the UPS depot. Under current business model this landed UPS with a bill just shy of £1m for the new substation even though they would need only a proportion of the output. UPS were too far gone to all out so they swallowed hard and paid up, but few others would or could do this.
@quinlet
Surely UPS can charge other electric vehicle drivers & operators ‘market rate’ to recharge their vehicles.
@LBM: But it would only make sense for the other vehicle drivers and operators to use the UPS charging facilities if they are reasonably near…
Unfortunately given the way things are going in London, deliveries will soon be done from locations in the outer suburbs such as Pitlochry…
This is an exaggeration of course, but with the green belt on one side and developers on the other and no sensible planning framework inbetween, that is where we will end up.
@LBM
And the charging was in the UPS depot overnight. There’s limited space and activity would prevent others from charging during the day. And when I say that UPS would only use a proportion of the output from the substation, it’s a small proportion.
Re Quinlet and LBM,
If a new substation (in the UPS case UKPN as the DNO not National Grid as the TSO) is required to meet increased demand from a particular customer outside the regulatory period development plans or timescales (very similar to the Network Rail control periods except they are now 8 years rather than 5) then the customer has always paid, UPS aren’t the first or the last*. Property developers will often wait till someone else takes the hit before proceeding with developments leading to increased land banking timescales. A significant proportion of wind farm cost is now network connection costs.
All the spare capacity on the new substation resides with the DNO not the customer unless they pay for the spare capacity.
Rule 1 of big development is speak to the DNO before you even speak to the council planning team or the lights won’t go on!
*Network Rail and LU will have paid a high 9 digit sum this decade for power supply improvements from Nat Grid and the Distribution Network Operators (mostly UKPN as they cover most of the 3rd and 4th rail network areas excluding SWML etc from Woking to further west) to be delivered to their timetables not Nat Grids /DNO timetables. National Grid have similar delivery on time issues as NR electrification schemes currently!
The Battersea PS and Wandsworth (ex Youngs) Brewery redevelopments were very lucky with their timing helping optimize costs some what as a counter example.
@NGH
Indeed, this is the very point I was making. But the question remains as to whether this business model remains appropriate today. Letting developers play the game of chicken to see who will cop the cost of the next substation is one thing, when there is a national policy towards getting more electric vehicles and the business model holds this up is another.
As some already pointed out, there are similar frequencies on the RER A in Paris during peak hours (theoretically 90 seconds between trains). Quite often you have trains entering platforms while the previous train hasn’t left the platform completely, I believe this helps for the high frequency.
The central part of the line uses some kind of in-cab moving block signaling system (called SACEM) installed in the late 80’s to allow those higher frequencies. With the previous classic signaling the maximum headway between trains was 2min30 if I remember correctly.
@TOMEK – -I suspect SACEM works on the basis not of moving block but the subdivision of a classic length block into many much shorter sections – the French were very keen on pushing that in the ’80s, at a time when moving block was still a theoretical concept. Maybe others have direct experience of the system?
To be fair, most, if not all metro moving block systems use the principle of a lot of very short virtual blocks. Eg 6.25m for the SelTrac system
What a great read! Coming from across the pond in New York, I greatly envy the ambition undertaken in London to bring a line up to 36 TPH! One of our subway lines, one that I take frequently, the L train will be shut down for approximately 15 months as repairs are made to its underwater tunnels that were damaged by Hurricane Sandy. This train line goes through some of the most trendy and rapidly-growing neighborhoods in the city, and ridership numbers have been soaring for the last decade. Rush hour trains are frequently jam packed, I often have to wait a train or two to pass before I can board at Bedford Ave. Yet despite being shut down for 15 months, all the MTA can promise is an increase from 20 to 22 tph, achieved by building some additional electric substations. The MTA won’t even consider building tail tracks at 8th Avenue (referred to as overrun tunnels here). MTA is clearly wasting an opportunity, sadly revealing that we simply don’t have the ambition to improve our subway the way that Londoners do.
Wasn’t quite sure where else to put this (no “contact us” page on the website)
[Snip PoP]
MilesT,
The basic rule is ‘if there is no where obvious to put it, then don’t put it anywhere’. We are not a bulletin board. There are plenty of sites that offer this service.
That said, an email to [email protected] would have been, by far, the best way of drawing our attention to this. We then have the opportunity of adding it to Friday Reads and means we maintain a modicum of control as to what gets published.
This reminds me of how in the 1980s an LUL planner proposed 40tph on the Northern Line in an internal memo (which I found, to my great amusement, in the mid 2000s). By the mid 2000s he was the GM of the Northern Line in its worst days as the “Misery Line”.
The Victoria Line can achieve 36tph for two main reasons: one, the inherent capacity of the new signaling/rolling stock combination; and two, that in the late 2000s, LUL timetables started being based on more realistic timings (how long it takes to get end to end) relative to actual conditions. The latter had previously always enforced the practical limit to capacity at LU, rather than the signaled capacity: increase frequency in a new timetable but under-provide run time, get chaos as a result, then do a service cut because “it didn’t work”. This is what happened with the Piccadilly Line “Big Bang” service plan. It happened again on the Northern Line: after the increase to 30 tph, and the resulting chaos from not lengthening the timings, the service was cut back. On the Central Line, more realistic timings were introduced end-to-end and this allowed for the westbound peak-of-peak service increase, without any change to technology. As for the ‘signaling capacity’ (which is really dependent on the vehicle’s capabilities in turn), the Victoria Line’s minimum reoccupation times at stations are in the 40-50 second range, compared to the Central Line’s 50-60 second range. I’m in ignorance of the specifics of the Victoria Line’s braking model, but I’m guessing that the presence of a vital accelerometer helped a lot with achieving the lower reoccupation times.