For many years TfL have run an investment programme grandly entitled ‘World Class Capacity’. Its worthy aim was to introduce a frequency of trains on the Northern, Jubilee and Victoria that could be considered world class.
This generally meant running 36 trains per hour (tph). As the years have gone by the objectives of the programme have been diluted with only the Victoria line achieving its original aims – an achievement it has only now (November 2019) finally achieved. We look at the programme, what it did achieve and to what extent outstanding items are expected to come to fruition.
Call it Railway Systems Enhancement
The original ‘World Class Capacity’ programme has now been absorbed into a new programme called ‘Railway Systems Enhancement’. Whilst we at LR Towers are generally cynical in the way TfL renames programmes (and so makes progress on them harder to follow), this renaming does make a lot of sense. As pointed out in the Programmes and Investment Committee, the new name contains ‘less hyperbole’ – a trend we hope is encouraged. The remaining aspects of the diluted programme certainly did not amount to ‘world class capacity’ on the Northern line and it was questionable if the term was still appropriate for the Jubilee line.
The other main reason for the ending of the World Class Capacity programme as an independent programme was that it made little sense to consider it in isolation as it needed to be co-ordinated with other, related, investment schemes. Most notable were the Northern line extension and Bank Station Capacity Upgrade.
Making some sense of it all
One of the problems for outsiders (like ourselves) attempting to make sense of TfL plans for the Underground is that we see a spread of objectives and target dates but we do not always understand the challenges that may lay ahead. When target dates are not met, sometimes by a number of years, it is easy to be both critical and cynical. This is especially true when not only are target dates quietly changed without explanation but the objective itself is quietly watered down. Moreover, the project is generally miraculously shown, once more, as being on schedule.
The latest Programmes and Investment Committee Agenda which was published back in October 2019, starts to provide some explanation as to the current problems that TfL have in meeting target upgrade dates on the Jubilee and Northern lines. The biggest giveaway is in part of paragraph 4.1.3 where it states:
With the signalling supplier committed to delivering works for a number of other programmes and the need to progress those works in a particular order, it is expected that the signalling software update on the Jubilee line will be delivered in time to support a frequency uplift on the Jubilee line in mid 2022.
Sad to say, as we shall see later, around one month after that committee meeting we have serious doubts as to whether that 2022 date could still be met.
The “other programmes”
Quite why TfL don’t clearly state what the previously stated “other programmes” are is a mystery since they often tell us how they are committed to transparency and openness. In any case, it is pretty obvious what the two major ones are.
The first is Four Lines Modernisation resignalling. TfL committee members have been told a number of times in the past that this is an absolute priority. Given that Thales is supplying signalling to this and that they also supplied the Jubilee and Northern line signalling, it is not hard to deduce that any delays with resignalling the sub-surface railway is going to have a knock-on effect on the Jubilee and Northern lines.
The second programme that obviously must take priority over any further Jubilee line resignalling is the Northern line extension to Battersea. Now, technically, this is not being resignalled, since it is new and has never had signalling, but this needs signalling installed and the intention is to install the latest flavour of the Thales’ CBTC automatic signalling system as found on Four Lines Modernisation. Note that this will not be quite the same as what is currently installed on the Northern line so there will be compatibility and transition issues but these should be minor in nature.
The critical signalling path
Whilst a lack of money for future projects is almost certainly the main factor delaying improvement and enhancement of the Underground, the lack of signalling resources for a truly modern Underground seem to be a close second. What is generally not appreciated is just how much of an issue this appears to be. With reports, subsequent to the committee meeting, of the next phase of the Four Lines Modernisation resignalling being delayed yet again, it seems that this is becoming more critical and it is getting to the point where it may be delaying upgrades over many Underground lines – in fact practically all of them with only the Victoria line appearing to be immune.
At present there appear to be only two signalling suppliers who can provide products that can cope with the rigours of the London Underground and it is clear that neither of these work ‘out of the box’. Or to be more accurate, both companies’ products work well in situations that have already been encountered elsewhere, or on the test bench, but become extremely problematic in a new scenario in the real world.
Current signalling suppliers
Siemens supplied the signalling for the Victoria line. They are also supplying the signalling for Crossrail in the central tunnel section. One big advantage in having Siemens supply a system for the Victoria line was that it was at the time the only system they were supplying in London. This meant that the project wasn’t competing locally for resources. It also meant that a delay to the project would not have impacted on any other project.
It is notable that Siemens refused to tender for the contract for Four Lines Modernisation resignalling which effectively made Thales the only viable bidder. The reason given for this was that Siemens realised that signalling the central section of Crossrail (for which they had the contract) was going to mean they would be too stretched if they won a bid for another large project.
Thales have supplied a number of versions of their current system to TfL. The original one in London was on the DLR. The Jubilee line followed on from that. Both of these implementations were very protracted as new problems were encountered.
In contrast the Northern line only posed a couple of major new challenges for Thales (a single track branch and a loop) and was installed relatively easily as they were effectively installing a system that (after a lot of debugging) was known to work. Thales are currently working on the major job of installing the latest iteration of their system on all of the Circle, District, Hammersmith & City and Metropolitan lines (the Four Lines Modernisation) and it is understandable that neither they nor TfL want them to be distracted from this task as its successful implementation will reap huge benefits. The trouble is that the Four Lines Modernisation is not due to have all the work installed before 2021/2 (and the project is slipping) which means that signal engineers are unlikely to start to become available before 2021. More worryingly still, the resignalling appears to be slipping at every stage. If the pace of implementation does not pick up it will be many years before all the work is complete.
Northern Line – recent history
The Northern line upgrade was originally proposed to take frequency to 36tph on most of the Northern line. This proved unaffordable which was not just down to the usual factors, such as the cost of new trains and beefing up the power supply, but also the considerable cost of providing sufficient stabling for all the extra trains needed. A more modest project that would generally provide around 30tph was substituted. This was to be carried out in two phases and a first phase would see 24tph on both sections through the central area and 32tph down to Morden.
In order to gain early benefits, phase 1 was further split with the relatively easy objective of 24tph (30tph to Morden) being its initial goal. This involved resignalling and some other works but no new trains. The seemingly simple enhancement to further increase the service to Morden from 30tph to 32tph then appeared to be very problematic and the goal then got reduced to 31tph.
One might think that the above objective could not be reduced any further without becoming meaningless but the latest papers show that 31tph actually means 31tph for just one hour in the morning peak and in one direction only. Thus the much-vaunted 30tph to 32tph has now become 30tph with a single extra train in one direction fitted in morning peak. Oh, and the proposed date of introduction has slipped even further. It now intended to introduce this extra train in 2021.
Phase 2 of the upgrade to the Northern line was cancelled. This was largely dependent on a project called Jubilee and Northern Additional Trains (JNAT). As this phase will no longer happen, it doesn’t seem as if there will be any significant improvement in frequency on any part of the Northern line in the next few years.
Where did it all go wrong?
Clearly a lot of the failure to improve the Northern line is down to the cancellation of additional trains. But that isn’t the full story and just about everything else can be explained by the lack of availability of Thales signal engineers.
The first problem seems to have been when the Northern line was resignalled for 30tph down to Morden it turns out that 30tph was really all that it could do. Given there were sufficient trains, if they could have run 32tph then surely they would have done so.
We now know that they can’t even get up to 31tph (one extra train) without a signalling upgrade, some extra track work (now done) and a power upgrade. They also need to install a wheel lathe at Morden depot so that an extra train is freed up by avoiding the need to send trains elsewhere to have their wheels reconditioned.
There have been continual suggestions by staff members on the District Dave website that Thales never really finished the job properly on the Northern line. Yes, it works for 30tph but there are still a lot of annoying non-critical bugs and there is no coasting feature – which is not essential but is nice to have and reduces heating in tunnels. It would not be unreasonable to believe that part of the reason for the work never being fully completed is that signal engineers were re-prioritised to work on Four Lines Modernisation.
The second problem is the one mentioned at the start with other projects taking priority. It seems that the idea now is to add the one extra train in the same timetable as the one that will be introduced on the opening of the Northern line extension to Battersea in Autumn 2021. The idea appears to be to optimise signal engineering resources by doing the work at the same time. Another factor could be not wanting to increase capacity down to Morden prior to temporary closure of the Bank branch (as part of the Bank Station Capacity Upgrade works) in order to reduce the number of passengers disrupted by this closure.
A possible reason for failure to implement 32tph
There is now some evidence that points to why the objective of 32tph from Morden has been abandoned for the foreseeable future. It appears that the signalling on the Northern line cannot currently handle 32tph due to the control units in the signalling system not being up to the job. However, the units are obsolescent and so already out of date and the more recent ones (as being installed during Four Lines Modernisation) would be able to handle this. An upgrade would be relatively cheap in relation to overall signalling cost and it makes the system easier to maintain but it does cost money that simply isn’t available at the moment. Of course, that presumes that the necessary trains can be made available from the existing fleet but that is another issue.
A baffling question
Completely unexplained in all the plans for the Northern line is quite how London Underground are finding the extra trains needed in order to open the Battersea extension. Even with only a 12tph service it is expected that they will need the equivalent of an extra three trains.
Originally, it was glibly suggested that the extra trains (originally five based on 16tph to Battersea) could be made available by increasing availability. But the trains are maintained by Alstom and there is no sign of any agreement for them to make more trains available. All they have agreed to is to provide one extra train for the extra morning peak train from Morden – and that they wouldn’t commit to that without the new wheel lathe.
One other possible solution for making more trains available is a new turnback, which was originally in the plans, proposed for East Finchley. However, the latest papers show no sign of this project going ahead and it appears to be one of many that has been quietly dropped.
A further, less likely, explanation is that the signal engineers manage to improve run times on the line to a sufficient extent that it provides the equivalent of three trains. This is a very tall order.
As we are mystified by there being no obvious answer as to how the trains are being provided, we will scrutinise carefully any future documents for clues.
Jubilee line recent history
Like the Northern line, the Jubilee line has a history of failing to live up to its promise.
The Jubilee line opened in its present form (with the Jubilee line extension) in 1999. At the time there was considerable optimism generally that the latest signalling was going to create a huge increase in capacity and a potential capacity of 36tph was promised. As with other projects relying on a technology just around the corner, it was not to be. The system could not be made to work and a late decision was made to introduce old-fashioned tried- and-tested two aspect colour light signalling. This, inevitably considerably reduced capacity.
After a lot of difficulty, Thales was able to introduce its automated signalling which eventually led to a 30tph service on the Jubilee line in the central section from Willesden Green to North Greenwich. This was the limit of what the signalling could deliver without further modification but another factor was there weren’t any spare trains.
As with the Northern line, an order for a supplementary batch of trains was cancelled so the signalling strategy, which was to have been to upgrade to 34-36tph was abandoned and an investigation was made to see what improvements could still be afforded.
One thing that could be built on was that, prior to cancelling all work on a further capacity increase, a turnback crossing at West Hampstead had recently been renewed. With this now available for daily operation, rather than just emergency use, it was concluded that it would be possible to provide 32tph between West Hampstead and North Greenwich. The catch was that even providing this would require further signalling upgrades.
Cancellation of JNAT – a blessing?
What no-one is saying, but now appears to be clear is that it is very fortunate that the Jubilee and Northern line Additional Trains (JNAT) project got cancelled. At the time the reason given was because the budget had to be revised downward to take into account reduced off-peak income over the whole of TfL. In retrospect, it is probably just as well it was cancelled because it is now clear that the increased service could not have been implemented without major work from the signal engineers and they were all busy on the Four Lines Modernisation programme. London already has enough embarrassment of many Crossrail trains being substantially under-utilised. Having yet more new trains sitting in sidings would not go down well with the public.
Of course, London Underground could have prioritised signalling related to JNAT over Four Lines Modernisation. The problem with this is that, in terms of cost-benefit, the Four Lines Modernisation resignalling would undoubtedly show a better case – not least because the necessary trains were already bought, paid for and in service.
It then seems highly misguided for one London politician, campaigning in the election, to have a pledge to try and get the additional trains for the Northern and Jubilee line reinstated. Politicians always underestimate the complexity of railway planning and we at LR Towers would encourage politicians to steer clear of such independently-thought-out ideas. From a political perspective such proposals are rather risky. Additional trains may sound like a simple objective but many factors need to be resolved including power supply, signalling, tunnel cooling and providing extra stabling space. If any of the necessary requirements are not in place then the promises made will not be kept.
The one that got away – the Victoria line
The great exception to all the woe provided by a failure to live up to proposals is contrasted by the success of the Victoria line. One might have thought that work here was already complete with a very impressive 36tph running in at the height of the morning and evening peak. However, yet again, the Victoria line shows what can be done with sufficient investment and a determined attitude.
On Monday 14th November 2019, there was a new timetable introduced on the Victoria line. Not for the first time, the date on the timetable is not the actual date it was introduced.
To quote from the working timetable:
The 36 trains per hour peak service has been extended to run for 180 minutes (3 hours), during the morning and evening peaks. During these periods, there will be no train service between Seven Sisters and Northumberland Park Staff Platform.
It is believed that the new timetable was dependent on upgrades to the depot. The basic problem was to get the 41 trains (from a total fleet of 47) into service quickly enough between 05.00 and 07.00. In fact the last train doesn’t get out until 0733 and the true 36tph (train every 100 seconds) service does not start until around 0720 and ends at 0950. Nevertheless what has been achieved is quite remarkable.
Despite what has been achieved, there is still a need for more on the Victoria line. Recently released data suggests that, actually, it would be desirable to cater for a four hour peak period on the Victoria line. Capacity-wise it is probably not essential but it would improve comfort levels. Whilst in the evening this should not be too much of a challenge, the difficultly of getting all the necessary trains into service so early in the morning would be considerable.
More than 36tph?
Coincidentally, on the same day as the Programmes & Investments Committee met, there was a talk at the Institution of Mechanical Engineers on the subject of ‘Towards common goals for engineers and transport planners’. The speaker was Geoff Hobbs, Director of Public Transport Service Planning at TfL. He specifically mentioned the Victoria line and explained to the audience why they couldn’t run more than 36tph.
As the above slide from the presentation makes clear the limiting factor on the Victoria line is the dwell time at King’s Cross southbound platform in the morning peak. You need almost every second of the 100 seconds between trains. Unfortunately, even if you could somehow cut that to 95 seconds, you would start to get the same problem at Highbury & Islington station so, as a minimum, it is desirable to solve both these problems.
Not mentioned in the talk but a few pertinent comments:
- It is presumed that Victoria station northbound is no longer such a critical problem as completion of the station works means that passengers spread along the platform more. This hasn’t increased capacity (whatever TfL have stated in the past) but has reduced dwell time.
- It is also presumed that there either isn’t a problem at the termini with turnround time or that a problem that solves the issues at King’s Cross would also resolve termini turnround time.
- Recovery time isn’t that important. Any delay will propagate to the end of the peak and then time can be recovered as the service starts to wind down. Nevertheless recovery time is highly desirable and shouldn’t be given up lightly.
- There are sufficient trains in the Victoria line fleet to cater for an even more intensive service – especially so if ’round trip’ run times could be reduced slightly.
The critical point made here by Geoff was that if the engineers, or anyone else, could solve the problem of getting the trains, say, only 95 seconds apart then there would be great benefits to TfL and its passengers. Such a solution would almost certainly be cost-effective and TfL would be keen to introduce an even more frequent service.
No good news
Given the problems of the TfL budget and the continued delay of Crossrail, it is difficult to imagine that progress on major TfL rail projects could get any worse. Yet to this mix we have to suggest that the challenges of modern signalling, necessary in order to substantially increase capacity without building new lines, is now becoming a critical factor.
It seems that any delay with Four Lines Modernisation will impact on future improvements on the Northern and Jubilee lines. After that comes the need to resignal the Piccadilly line. This has already been postponed due to monetary constraints but the fear is that it could be further delayed by the challenge of getting a signalling system working that could support the proposed frequency (32-33tph). All subsequent projects (including the Bakerloo Line Extension) could be similarly delayed. Meanwhile, it is well known that when existing signalling continues to be used beyond its designed life it starts to fail more often leading to considerable passenger delays. For all lines except the Victoria line, the outlook is not good.
An upgrade would be relatively cheap in relation to overall signalling cost and it make the system easier to maintain but it does cost money that simply isn’t available at the moment.
And there is that other problem, TfL’s shortage of money – for various reasons. And which I don’t think it’s relevant to go into in this article, or not right now, anyway.
But that money shortage is definitely “biting” isn’t it?
Your meeting report is appreciated. All efforts at transparency are important to the community for a shared understanding of the challenges.
[Cheers for the error checking, all corrected. LBM]
PoP – your usual masterful analysis; thank you.
A minor quibble and a few points:
Quibble: The “latest flavour of the Thales’ CBTC automatic signalling system as found on Four Lines Modernisation” is probably a little OTT. I’d accept that the key control elements – the Vital Control Computer etc. might be the latest flavour, but the NLE will still use the loop communication system with the trains. So it’s components, not the system!
Points:
Providing the extra trains to run the NLE and the extra TPH is effectively squeezing the 1995 tube stock fleet availability for all its worth; the wheel lathe will help, but I’m sure TfL’s supplier will be rewarded for the extra squeeze!
The 36TPH on the Victoria line is being delivered with two trains fewer than was originally planned for the PPP 33 TPH. That’s the true measure of the success of new trains with signalling carefully fitted by experts to the performance of the trains and the needs of the infrastructure – and some track and power work.
It’s interesting that nothing changes in that it was 35 years ago when LU was seeking to improve the Victoria line service by adapting some 1972 tube stock cars to increase the fleet to allow a higher frequency and, even then, King’s Cross/St. Pancras SB was a constraint. The constraint was resolved by installing an additional signal – effectively an additional home signal – on the approach. The new Victoria line signalling is still “fixed block”, albeit with some very short blocks, especially in and around the stations with the longest dwells. I have little doubt that the clever folk that developed the Siemens signalling could come up with some additional ideas to further reduce the re-occupation time into the critical platforms. However, as you highlighted, Kings Cross might be the critical location with Highbury & Islington not much better, but the southbound chart shows that Finsbury Park, Euston, Warren St, Green Park and Victoria are “on the cusp”.
There must be a finite capacity for a tube line and I wonder if 36 TPH is that limit? We always wondered what our successors’ successors would do next time all the assets need renewing. Will there be any new techniques to squeeze more capacity?
“Given that Thales is supplying signalling to this and that they also supplied the Jubilee and Northern line signalling, it is not hard to deduce that any delays with resignalling the sub-surface railway is going to have a knock-on effect on the Jubilee and Northern lines.”
I think this is the wrong way round.
@130
There are metro systems that operate reliably at 40tph that are not fully automated (e.g. in Moscow) – https://tass.ru/moskva/524277
The difference is, the stations are designed far more generously space-wise than the victoria line, with completely level boarding and wider trains (due to the broader guage), which reduces dwell times considerably. The recent practice in the UK of avoiding reversals in sidings rather than on platforms is also a limiting factor.
I do think more than 36tph is acheivable, but it will come at a heavy cost. At such high frequencies dwell time is critical – and with ‘tube’ trains reducing it becomes much more difficult.
If money were no object, how much would it cost to add an additional platform on the other side of the south bound Victoria line at King’s Cross and Highbury & Islington, and open the doors on both sides of the train as they do at Stratford Central line westbound?
It’s the lack of the continuous and spacious central concourse between the platforms which is surely the main problem in the historical central London stations, when compared to say Moscow. It makes a massive difference in the JLE stations and indeed rebuilt ones like London Bridge on the Northern Line when the passengers can quickly get off the platform to a spacious separate area, before exiting or changing lines.
From the Victoria Line at Oxford Circus for example, while there is a a cross platform interchange and a central concourse it’s not continuous, so to exit or make any other interchange you have to walk along the platform to the correct part, thus potentially getting in the way of passengers getting off the next train.
TfL had little influence on the new Vic Line trains provided under PPP, which are low risk version of traditional tube train as seen for 75 years. TfL were developing the Space Train concept until then, which would have seen greater capacity. If they could now have a Vic Line version of the new lightweight Picc train, a development of Space Train with walk-through cars, air con, and all double doors, they could cut dwell times, add around 10% capacity, and maybe reach 38tph, a further 6% capacity, under current signalling, vent, stations, etc.
CXXX & others
You have noted the dwell problems at Highbury, as well as King’s Cross.
I’m fairly sure this is to do with the internal station layouts, as much as anything else.
I’m a regular user & the congestion is v high – not as dangerous & frightening as, say Holbon on the Picc-line, but unpleasant nonetheless.
A third escalator in the middle set of steps would help, as would the proposed re-opening of the “Original other” entrance.
But, of course that also would take lots of money that TfL don’t seem to have right now.
Jono
That would require moving other tunnels as well, wouldn’t it? Tunnels of differnt sizes, too!
Remember at Highbury the tunnel arrangement W-to-E is: N’bound Vic, N’bound GN&C, S’bound Vic, S’bound GN&C.
Suggestion: look at Carto Metro’s plans before making suggestions of this sort … as it’s a lot more horribly complicated than many people suppose.
100andthirty,
Yes it is the components. Sorry if this is not clear. I think of it a bit like upgrading a burglar alarm by opening the control box and putting in a new control board. Most of the installation is the same but you effectively have a new alarm system. Of course you might upgrade a few other items as well but it is still more-or-less the original system with the original wiring (assuming a wired system).
There is another potential benefit with an upgrade and that is to reduce the number of signalling areas and hence the number of boundaries. This was done on the DLR to remove a boundary at an awkward point. This benefit is analogous to Southern Railway in the 1920s where quite new modern (for the time) electrical signal boxes controlling four aspect lights were merged to create efficiency savings and operating benefits.
I think what Geoff Hobbs has effectively highlighted is that 36tph on the Victoria line is the maximum possible frequency currently possible. Or at least currently identified. If it becomes possible with existing stock and signalling then it is going to be either because of a new idea (which I think is unlikely) or a tweak in technology, not currently possible, that is just enough to provide that extra vital few seconds.
Greg Tingey,
You may have a point about King’s Cross. The lesson learnt from Victoria is that with better passenger flow you can reduce dwell time as people are better spread along the platform. However, this will do little for capacity unless it enables a more frequent service to be run. One of the advantages at Victoria, which I am sure was never designed for, is that it is relatively easy to stop people entering by the direct route from the main line station and quickly reduce the overcrowding level on the platform. I suspect the same is not true at King’s Cross.
I’ve never used the Northern line south of the river. Normally tube lines get quieter the further out of London, yet this suggests there is demand for 32tph to Morden, is this a particular busy part of the network outside of zone 1/2?
Re CHRIS KEENE @ 16:18
Yes…
In the mornings it tips from fully loaded (TfL definition = less than or equal to 4pax/sqm standing) at Tooting Bec to over loaded at Balham (greater than 4pax/sqm standing) and is wait several trains / unboardable at Clapham Common and Clapham North. It then empties out a bit at Stockwell then gets overloaded at again Oval to Kennington (empties out a bit ) and then over loaded again from London Bridge to Mooorgate.
It is also worth noting that Tooting Broadway is a major bus heading destination from wide area with overall passenger numbers similar to Fenchurch Street!
Great article as usual.
The poor old Jubilee is in for a squeeze before Crossrail – and not long after. The eastern stretch still has a large amount of unused land.
Work on thousands of homes by West Ham station looks to finally be underway.
North Greenwich has seen its masterplan increased again this year to near 18,000 homes. Nearby Charlton Riverside hasn’t seen a home yet built and already increased from 5-7.5k homes to 8k. Other in the area total around 4k.
Canada Water had its masterplan approved a couple of months ago. 3k+ homes.
Canning Town has a large number of blocks now rising. Many more planned in the area. About 5k homes?
Canary Wharf and Stratford see much growth of course.
I’m going to file away the “these should be minor in nature” comment on the Battersea extension signalling for a later date. I can guess at why it’s being done like this, but updating train software to support 2 signalling systems is … interesting. Expecting trains to switch between them seamlessly every time when entering and leaving the extension is … a brave decision.
Don’t doubt that there’s been lots of internal discussion on the pros & cons of this and it’s likely to be the least worst solution (within the constraints given to the project teams) for all sorts of reasons that I’m not privy to.
( And if it works passengers won’t even notice to say “good job”.)
It seems that London is crying out for more from the metro signalling market. Not sure about what the global level of demand is, but anecdotally I always seem to be reading about new schemes being green lit all over the place.
Are none of the other big players making moves to develop products that they could meet this demand with? Notwithstanding Bombardier’s disastrous foray into metro signalling under 4LM, Alstom and Hitachi (formerly Ansaldo) seem to be absent from discussion.
It feels to me like UK rail (i.e. NR, TfL et al) need to bite the bullet on this and start to build up some form of publicly owned in-house signalling enhancement capability. The market has demonstrated on many occasions that it cannot effectively meet the demands placed on it by both metro and main line signalling schemes – feels like something more drastic has to be done.
I thought the constraint on the Victoria LIne was the run in and run out times at Brixton & presumably now Walthamstow. The station configuration results in uneven departure headways as if a train is taking the straight route into the southbound platform at Brixton another can leave the other platform at the same time using the straight route. The next train then has to use the cross over to get to the now empty platform and this delays the departure of the first train that also needs to use the other part of the cross over crossover to go Northbound. This really needs a diagram to show what happens.
JohnM,
I thought that too but I am going by what Geoff Hobbs said and the fact he didn’t mention turnaround capacity.
From what I know of Geoff I think it is unlikely he would get his facts wrong.
I did mention in the article that this presumes there isn’t a problem with turnaround time or that a solution for King’s Cross also provides a solution for cutting turnaround time.
I’m still baffled why signalling is not a solved problem. It seems that constantly improving technology just makes the problem worse, as new systems are basically obsolete as soon as they get through the procurement process.
@JohnM @PoP
The way I understood it was that the replacement of the Brixton Crossover in in 2000 and the Walthamstow crossover in 2015 enabled a much higher capacity service to run over both.
If the trains can transit the crossover at sufficient speed, such that it only takes a few seconds, and the points can move and signals clear in a similarly short time, I could imagine there’s no longer so much of a constraint. Each train has to make one transit of the crossing and one parallel move as they turn around, so I imagine departures are timed to reflect that as you suggest, so that an evenly spaced service arrives at the next station.
PeterW……..”I’m going to file away the “these should be minor in nature” comment on the Battersea extension signalling for a later date. I can guess at why it’s being done like this, but updating train software to support 2 signalling systems is … interesting. Expecting trains to switch between them seamlessly every time when entering and leaving the extension is … a brave decision.”
There is no switching of systems. PoP was referring to the innards of the central signalling system, not what the train sees. Trains moving across the boundaries of Vital Control Computers is a feature of the Thales Seltrac system.
Re Victoria line, JohnM is right that the crossovers at Brixton and Walthamstow are a constraint. They allow trains to go as fast as the tunnel spacing allows, and this was improved when the crossovers were replaced, but trains can’t quite run in and run out on the natural deceleration and acceleration curves. For every train either run in OR run out is constrained. However the impact is small and the timetable is flexed slightly in both direction to accommodate this.
Excellent article as ever PoP.
Lots of talk about the need for a wheel lathe at Morden. Estimated cost?
Re IAN SERGEANT
£3/4m as starting point depending on spec.
R.e. Northern line overcrowding.
There’s another new development (18 stories, 1,300 homes) being built in Kennington and tens of smaller schemes as the area is in-filled.
Kennington station is also the closest station for some commuters from the new Walworth road developments.
So that’ll help make sure any remaining spare capacity on the southern reaches of the northern line us used up!
Chris Mitch
I’m still baffled why signalling is not a solved problem.
Partly because it’s not a fixed problem.
It isn’t “just” the modern difficulty of software becoming obsolete the moment it’s written, nor improvements real or imagined in computing abilities.
It’s that the operators & the infrastructure owners also see these imporovements & immediately ask the signal engineers to do “more” & “better” & “faster” & “with bells on!!”
There’s also the v modern problem that it’s no longer a matter of fitting (say) an AWS detedctor to every locomotive & unit. You have to have, even with modern minaturization, quite bulky boxes of “Kit” stuffed somewhwere into your moving units & these must themseleves communicate seamlessly & with at the very least 99.99% reliability with other signalling components elsewhere – on the gound, between the track, up radio masts, etc.
You are trying to hit not just a moving target, but one that is changing in both speed & direction, as well as both metaphorically & in physical reality (!)
I wonder why with the obvious gap in the number of signaling engineers being known about years ago, that we didn’t go out and train some more up so that all these projects could go ahead at the same time.
JC
There was a recruitment ban on new signal engineers, approx mid-1992 until about 1995, maybe a bit longer.
This was at the then government’s insistence, because Old BR was “deeplyt ineficcient” – or so they said – & even when the “new” companies took over, at actual privatisation, IIRC, recruitment was very slow at first.
This has now worked it’s way through the system.
Re JC @ 12:31
In this particular case (SSR / Northern / Jubilee) it is a Thales issue and also includes the software side so is a global issue for them. They also have several parallel nightmares (involving crunched trains due to software) schemes round the globe (Singapore and HK being the worst) that make the SSR resignalling look good. Thales work with LU has uncovered new software defects in tried and tested software…
There is a global shortage of signalling engineers – the big blockades for the Thameslink programme saw them travelling in from as far as Australia.
If you train some up, they will get snapped up elsewhere.
Of possible interest is that there will be a temporary Northern line timetable from 30th December 2019.
Given that the implication is that it requires signalling work to restore berthing capacity on the Kennington loop it will be interesting to see how long this temporary timetable remains in force.
Great article. My own experience of the Victoria line – southbound from KXStP in the high peak – is typically waiting for the third or fourth train before being able to board. But with no prospect of improvement possible, what next for the hard pressed (in every sense) Vic Line passengers?
Crossrail 2 anyone?
An interesting article. I always consider myself very lucky to live on the Victoria line. It seems to be the one that got away (from some of the capacity constraints). I always wonder how much that has to do with it being a newer tube line (relative to the other deep tube lines). I know there was the JLE but that is obviously only relevant to the eastern part. Was the Victoria line over engineered in the 60s maybe and now it is seeing the benefits? Though I seem to think I read an interesting article on here some time ago that depicted money being very tight at the end of that project.
Irrespective, with enormous housing development currently underway at Blackhorse Road and some pretty big housing projects happening at Tottenham Hale, I suspect this issue of southbound capacity at HBY and KGX is only going to get worse when development is completed further north…
Not only Moscow, but also Paris runs 40+ tph on a regular basis (i.e. line M14 runs 42tph with about 70% the ridership per km of the Victoria line). I don’t know what station sizes they have. But it seems London has room for improvement.
Eric,
We have been through this a number of times. Not really quite sure ligne 14 manages 42tph but I will take your word for it.
In Paris there is a different mentality both societally and legally. Ligne 14 (and ligne 1) are completely unattended as regards driver operation. The doors shut automatically (quite hard) after a given length of time. If you are injured then it is pretty much automatically considered to be your fault. The ‘duty of care’ so enshrined in tort law in the UK is not present to the same extent.
If, on the Victoria line, you could just slam the doors shut after a given length of time regardless of consequences, I am sure 42tph could be achieved here. It does raise the next point which is whether a high frequency that is achieved by stopping people boarding due to insufficient time actually improves capacity. More likely it reduces it.
POP
which raises the interesting point that 42tph three quarters full gives more capacity than 30tph so rammed that station stops are extended.
Has controlling the flow of passengers to busy platforms been examined from a capacity point of view rather than just safety?
Regarding Paris Metro, I believe the 85 second headway is also facilitated by the fact that the trains are shorter and can be reversed faster, compared to London Underground.
Tommy L4
Not sure that it actually matters, really.
As an example, I was recently going to catch a Vic-line train at Walthamstow & one came in late ( Both platforms were empty ). But, because all trains are stepped-back, there is no wait for a driver, or physical end-changing.
Total turn-around time was approx 50 seconds – the new driver was making announcements that “This train is about to leave now, if you want to go to Walthamstow, please get off – now!”
I think the problem with “ramming” at places like Kings Cross, or Holborn, is simply that the platforms are too narrow, so that neither borders nor alighters can move freely.
We covered ligne 14 a number of years ago.
As part of an official organised party I have actually seen first hand how reversal is done.
The horn sounds and passengers are then told to leave the train as it is at the destination. Then the doors close automatically and the train departs at speed into the sidings so it can use the crossover to reappear on the other platform. We had been given special permission to stay on the train. The acceleration and deceleration was severe and clearly done on the basis that there was no-one on the train. It would not be acceptable for an in-service train. Also, if I recall correctly, the reversal was almost instantaneous.
So no comparison with the Victoria line and not something that would be allowed in the UK under current rules.