If a Train Operating Company (TOC) needs to buy a fleet of electric passenger trains for its network the process is pretty simple. All the main manufacturers have standard models which can generally be configured to the client’s specification. Currently, they can be purchased with relatively short lead times.
A glut of main line train options
This reduction in the difficulty of purchasing trains is a recent thing. Indeed we have seen a spate of new designs (such as those for Crossrail, Thameslink and the Intercity Express Programme) that have given rise to a new set of base designs that can be tailored to suit the requirements of an operator. It has also led to a different emphasis in franchising. The DfT no longer feels a need to get involved with train design and purchase. Instead, it can weight the franchise criteria to encourage replacement stock when appropriate (or even when it is not). The potential TOC can then propose a particular rolling stock solution in its bid and, if successful, the new rolling stock can be brought into service in the first few years of the franchise. The time lag between winning a franchise and commencing operation means there is potential for trains to be in service very early in the franchise.
Crossrail’s rolling stock being tested at Derby
The TfL approach
Of course, if the TOC wants something special then risks increase and lead times lengthen. On most mainline franchises this is generally to be avoided, but if you are TfL then there is a requirement to think longer term. As recently as 2009 London Overground brought “walk-through” class 378s from Bombardier into service when, at that time, it was most certainly not an “off the shelf” option. Non-standard too, at the time, were side-mounted cameras with displays in the driver’s cab, so that the train could be Driver Only Operated (DOO).
Inside London Overground’s 378s. Photo by Peter Skuce
For TfL, not limited by the length of a franchise, the delays and risks involved in introducing novel features are worth it for the benefits in the end product. A further advantage is that once the technology is established it should be easier to specify the same requirement next time.
You have to live with your mistakes
This approach, however, is not without risks and problems. A train that has to be highly customised for the network it is to run on – such as the Underground, for example, will normally have little second-hand value. For its operator, this means accepting that it may be stuck with it for up to forty years or more. This makes any faults in the design or a failure to take advantage of the latest beneficial technology expensive and inconvenient prospects – ones that may endure over the lifetime of the train. The single-leaf doors of the D78 District stock hampered loading and unloading for 37 years, for example, and the 1983 Tube stock had to be prematurely retired. This was because the single-leaf doors on those trains were completely unsuited for a very busy Jubilee line extension.
The 1983 stock at Neasden Depot. Photo by Beechwood Photography
New Tube for London – jam tomorrow
All this means that London Underground trains often need a long lead time from the initial decision to replace the rolling stock to the new class coming into service. The relative speed with which the Sub-Surface S Stock entered service was more the exception than the rule (and the accompanying signalling upgrade is not expected to be operational until the early 2020s).
Concept image for the New Tube for London. Courtesy TfL
The Deep Tube Programme, featuring the New Tube for London, has been closer to the norm. As has been well documented on this site and elsewhere, delays to this replacement programme have led to the need to carry out some major reconstruction and refurbishment of existing Tube trains – most notably the Bakerloo line rolling stock. The need to expensively repair existing body-frames buys time, but it cannot be considered a cost-saving measure. Nevertheless, the importance of getting a less-than-once-in-a-generation final product right means delaying ordering until the product is fit for purpose, and the money is available for it, is almost certainly the correct thing to do. The downside is not only a need to soldier on with the old stock, which is becoming expensive to maintain, but also customer dissatisfaction with the dated travelling conditions.
DLR trains have the same problems as Tube trains
In London, in the same category as Underground trains are those to be found on the DLR. The nature of the line, largely above ground but with an underground presence, means strict fire regulations apply. It also features a number of exceptionally tight curves, has no requirement for a driving cab and has restrictions on train length. This means that one cannot just buy standard trains for the DLR off the shelf. Any rolling stock order has to be to a bespoke specification.
Original DLR rolling stock. Photo by PLCD.
A history of piecemeal purchases
Early testing on the DLR at Devon’s Road.
Until now there has been an ad-hoc approach to purchasing trains for the DLR. As the network was extended in phases, new trains were purchased for each new phase. Some of the earliest trains were sold on very quickly when it was realised how inadequate they were for the growing network. It was fortunate on that occasion that relatively few trains were involved and a buyer could be found who, after instigating considerable modifications, was able to reuse the fleet in a less demanding role.
ex-DLR rolling stock in use in Essen. Photo courtesy of Alfie.
ex-DLR rolling stock pulling into a station in Essen. Photo courtesy of Alfie.
Indeed when the network opened it did so with long, single-unit articulated cars. When it was decided to double the train length, the solution implemented was somewhat direct – pairs of the original cars were coupled together. This meant that there was no internal connection and that space was wasted where the trains were attached in the centre – even if they didn’t have a driver’s cab.
DLR trains navigating the curves of Delta Junction.
Perhaps more surprisingly, when the trains were extended again to three cars the decision was made to take a similar approach. Almost-identical single articulated units of the same length as before were ordered and coupled on again. The decision was much queried and criticised at the time, but TfL partly justified it on the basis that no manufacturer would be willing to offer anything else at a reasonable price – something not entirely believed at the time by some rolling stock engineers.
Flexibility more important than capacity
This wasn’t the only reason given for the decision. It was also said that not all trains would run with the three-car configuration. Off-peak and at weekends they would only run as two-car units. As events turned out, the idea of running two-cars off-peak during the working week never really took off. No doubt the DLR discovered, as had many railway operators before them, that the effort of attaching and detaching stock during the day not only caused performance risk but also meant that any potential savings were offset by the need to provide additional staff to carry out the manoeuvre. Also, as a consequence of limited depot space to store trains of three-car length, the DLR also learnt that continued attaching and detaching caused maintenance problems with the trains’ couplings.
DLR rolling stock at Stratford International. Photo by PLCD.
The eventual running of all trains, seven days a week, between Bank and Lewisham as three-car trains also made the three individual cars per train configuration even less than ideal. In the end, it seemed that the only benefit of the separable cars was the lack of depot space configured for three-car trains.
The Olympic salvation and a bittersweet legacy
For the DLR, the Olympics was both a blessing and a curse. It was a considerable blessing because money was made available by the Olympic Delivery Authority for more desperately needed trains when TfL was already in the middle of a massive (and costly) train purchase programme. When you are already paying for one S Stock train one London Overground train a week, there is not a lot of money available to go and buy trains for the DLR.
The Olympics was also, however, a bit of a curse. The timescales involved meant delivery could not be delayed beyond a certain date under any circumstances, and this naturally restricted innovation and prevented a bold approach. This isn’t to say that the new trains were simply clones of those already in service on the line. They were much more technically advanced – just with well-established state-of-the-art components. The opportunity to innovate was thus lost. Ultimately the trains were built to an existing design that was known to have imperfections and these latest units are thus not without their problems.
DLR unit 109. Photo by PLCD.
After the Olympics, the general impression given was that new DLR rolling stock would be ordered as soon as it was prudent. Passenger growth remains strong. Latest figures suggest 4% this year, but more generally it has been at around 6%. There was an expectation of massive growth on the Beckton branch with the Associated British Ports Development by the Royal Albert Dock and increased frequencies were planned for various parts of the network.
The familiar story of slipped dates
The hope originally seemed to be that new stock could be introduced around 2016. This would have tied in with construction work around Albert Dock and one of the things the Olympics has taught us, if not already known, is that you ideally need to have the service ready for the construction workers and not wait until the development is complete.
As is often the case, things didn’t work out as hoped. To delay things further, it was recognised that the opening of Crossrail was expected to cause a slight dip in passenger numbers on the DLR, one that would recover around three years later. So once the early targets weren’t met it was thought that the best option was to carry on with existing stock until around 2021.
At last – signs of an order due
As a result of all the above, it came as no surprise to see the March TfL Programme & Investments Committee meeting look at a paper about the DLR Rolling Stock Replacement Programme. Indeed the surprise would have been that it had not been presented sooner but, with a change in Mayor and a consequential desire to overhaul membership of the TfL Board as well as reorganise the functions of various committees, there does seem to be a backlog of projects for approval – only now being addressed.
Helpfully a timetable proposed timetable is included.
Note the plans to extend and expand the depot (as a separate contract) in time for the new trains.
The proposal document puts forward gives sound reasons for replacement of the fleet. Somewhat surprising is the statement that the design life of DLR trains was only 25 years. Given that Underground (and Overground) trains have a design life of around 35-40 years, as do trams, this seems on the low side. Then again it may be accounted for by the exceptionally harsh conditions that DLR trains face. Stops are rarely more than two minutes apart, nearly all trains operate for most of the day (meaning 18-20 hours in service) and run more-or-less seven days a week. Then there are the tight bends and steep inclines. Arguably, all the more reason for making sure the next generation of trains is fit for purpose.
The proposal document also issues a dire warning:
4.14 The new trains are required by 2022 to avoid up front, expensive, life extension costs and additional operating costs associated with staffing stations (most DLR stations are currently unstaffed) due to overcrowding. It will also minimise the amount of ‘patch and mend’ expenditure required on the current fleet.
As on the Underground, it is thus the case that if new rolling stock does not arrive to schedule then a lot of work will be necessary to keep the existing trains in service. Not only does this mean it will be longer before DLR users get the benefit of new trains, but it also means existing stock will inevitably need to be taken out of service for remedial work. The trouble is, the current DLR timetable is run on the assumption of incredibly high stock availability. This can be adhered to now, but any significant refurbishment will almost certainly, at a minimum, lead to shorter formation trains.
Nonetheless, it did appear that everything had at least been sorted. In the true British way, especially when it comes to transport, this would all be done just in time – providing there were no unexpected problems.
It seems it is too late
Given that everything seemed to be wrapped up and resolved, it was quite disturbing to read on IanVisits that Plant Engineer reports that DLR trains are undergoing extensive works offsite. This is to deal with cracks in the subframe, as thoroughly clean and inspect the frame and to deal with any other issues that may be found.
This report would appear to contradict the argument presented in the proposal for new DLR trains unless you take this fairly major undertaking to be the minimised ‘patch and mend’ referred to. For a minimised solution it is fairly extensive.
In the Plant Engineer article, a fourteen-day turnaround is discussed. Given that the article suggests 76 cars are being overhauled then, with one car out of service at a time, this would take around three years – completing in 2020 just one year before it is hoped the first of the new trains will be delivered. There is one caveat, however: what is unknown is when this process started. The article in question ends with the statement that:
To date, every frame that has passed through the process has been returned on time.
This suggests that the process is already well underway.
At last an invitation to tender
It is, of course, worth asking whether these repairs are intended not just to be a precursor to a new fleet but a replacement for it. This would be a major cause for concern and one not entirely out of the question given the pressures on TfL’s budget. Fortunately this appears not to be the case. An alert District Dave’s Forum contributor spotted that an OJEU notice for the new rolling stock was issued on 12 May.
Of particular relevance here are both the quantities and the confirmation of dates.
The initial requirement is for 43 new trains with the first 3 trains currently planned for delivery for final acceptance testing by June 2021 thereafter entering revenue service from June 2022. The remaining trains within the initial requirement are anticipated to be delivered from July 2022, with the 43rd train entering revenue service no later than June 2024. In addition to the initial requirement, the contract for manufacture of the new trains will include options to purchase up to 34 additional trains.
The dates involved suggest both that earlier proposed delivery schedules have been blown out of the window and that when the trains finally arrive they will be desperately needed – especially on the Beckton branch if developments proceed as planned.
Testing, testing, testing, one, two, three…
Note that a whole year is allowed for in the schedule for pre-revenue testing and training using the first three trains. This prolonged testing phase is not exceptional. Indeed it is a feature of the modern rolling stock and signalling world. London Overground ran services to Clapham Junction for six months prior to passenger use and Crossrail plans to spend the best part of a year testing services in the tunnel through the central core. This is all part of the “get it right” mentality. It should make it possible to rectify any major problems before the production line starts producing trains in earnest.
More, more, more
Note also the option to buy up to 34 extra trains. If every existing train was scrapped and the option was taken up on all 34 trains that would mean a total of 77 trains – equivalent to the three-car trains of today. This represents an increase of 28 trains – 57% more than in today’s fleet. If proceeded with it suggests, at the very least, a much more intensive service for the Beckton, Canning Town – Stratford International and Stratford – Canary Wharf services. Indeed an appendix on the final page of the proposal document gives possible suggestions as to how these 34 extra trains could be deployed.
A challenge
The slight concern is that the timetable, as ever, seems challenging. The interested manufacturers will probably have around six months to put together a proposal and the successful one will have around three years from being awarded the contract to having to deliver the first three trains. If this was a standard, off-the-shelf train then this would be ample but the schedule does seem tight for what will effectively be a sophisticated bespoke product.
Déjà vu?
Overall, both the report and the tender notice seem to confirm that it is largely the lack of rolling stock that is holding back plans for enhanced services. There also appears to be the need for a heavy overhaul on the existing rolling stock just to keep it in service. The good news is that in the long-term DLR users will see the benefits of all (or at least most) of the line’s trains being upgraded to modern rolling stock suited to the DLR of the 2020s and the 2030s. As with the Underground, however, it is hard to escape the feeling that this process really should have happened sooner.
With the Bakerloo holding a tradition of being assigned with stocks cascaded from other lines, one might wonder why not overhaul some newer stocks on other lines (e.g. 1992 stock) for its use while giving new stock for the line having cascaded them away, but it looks like the process isn’t going to be sped up this time.
Where is the hard currency coming from? Even trains built at Derby or Newton Aycliffe will need some parts imported.
PoP…………A pedantic detail………You only mentioned this by way of introduction, but you say that S stock introduction was fast. I’d disagree. I’d say that S stock was initially organised away from the glare of publicity because of the over-riding issues with the PPP. The contract for S stock was placed in April 2003, design work started in 2005, first train in service, 2010 and the last D stock removed in April(?) 2017. Overall, 14 years – steady and measured in my view, not fast!
I think the first image needs checking – I get the crossrail logo rather then a train under test?
Fascinating, tyvm – my office looks down on Canary Wharf Crossrail (and Delta Junction!) and it certainly feels like it will be full on Day One, bit I’m surprised that the respite fur the DLR is so short.
(Typo of LDR about halfway through.) [Fixed, cheers! LBM]
As a side question: Do TfL ever plan on using the 4th car platform space on the Beckton branch? I was riding on that branch the other day and it looked like the platforms could hold a 4th car.
Also a typo: When you are already paying for one S Stock train one one London Overground train a week. [Fixed, cheers! LBM]
@Drew: Definitely not just you, I’m seeing the CR logo as well.
Asian Business Port; Some of us have met Mr Xu.
“There was an expectation of massive growth on the Beckton branch with the Associated British Ports Development by the Royal Albert Dock and increased frequencies were planned for various parts of the network.”
If I was an interested manufacturer, I would already have been drawing up designs in the knowledge that an OJEU notice would be coming along within a few years – so I don’t think the apparently short timescales are necessarily an issue.
Noticed a stray LDR under the ‘DLR trains have the same problem…’ section. [Fixed, thanks! LBM]
Otherwise as a DLR fan this is both encouraging and in line with the final sentence slightly depressing!
I wonder if the new rolling stock will be derived from a tram? After all, trams need to cope with similar curves and inclines to those found on the DLR…
A great article but could have done with another proof read to maintain LR’s usually high standards.
Is this a previous version fo the article rather than the final proof-read one? There are dozens of errors sprinkled throughout.
There are two other similar train procurements underway at the moment – Merseyrail Electrics and Tyne & Wear Metro replacement.
Stadler won the former 52 train order with a specifically-designed train: four car articulated units with lower floor levels and extendable steps to provide full accessibility. Fleet to be introduced by 2020. Bombardier, CAF, Siemens and a consortium of Mitsui, Alstom and East Japan Railway’s rolling stock manufacturing business J-TREC had also been shortlisted for the rolling stock contract.
The T&W fleet specification is out to tender at the moment, so will be interesting to see who bids and whether they’re proposing to adapt existing products or start from scratch but drawing from existing technologies and systems.
The question will be whether TfL/DLR will accept any small changes to receive a slightly more standard design for a potentially lower price, or will it stick rigidly to its specification and possible have to pay accordingly.
Manufacturers seemingly are interested in fleets such as the DLR’s, able to draw on existing traction packages and technologies packaged within a bespoke skin. Given the fully segregated nature of the DLR, it might be easier to design a new fleet as crash worthiness testing may be less onerous than on national rail.
I can’t help but wonder if “Deja Bakervu” would have been a more catchy title?
I wrote a post last week looking at housing and airport development on the DLR branch from Canning Town to Woolwich. Even a three year dip in passengers due to Crossrail could be optimistic. The number of high density housing blocks on the route is vast and most are on the doorstep of DLR stations but a decent sized walk from Crossrail, negating faster journeys on it once the walk is taken into account. Royal Wharf will cause a big squeeze even before Crossrail opens.
https://fromthemurkydepths.wordpress.com/2017/05/14/a-look-at-developments-along-the-dlr-between-canning-town-and-woolwich-arsenal/
Five to seven years is a long time. Hopefully the predictions on passenger numbers are correct.
As a side question: Do TfL ever plan on using the 4th car platform space on the Beckton branch? I was riding on that branch the other day and it looked like the platforms could hold a 4th car.
Not all of them – Royal Albert, for example, is still only 2 cars long (I’ve often wondered why, given it’s not constrained in the way places like Island Gardens are) and of course trains from Beckton run through to other branches which only have up to 3-car platforms.
Sub-Service S Stock? Sub-Surface, Surely [Now fixed.]
The new Mayoralty has caused some delays but I think the major problem here, as with other major projects, is the TfL Budget. There’s no money for major rail capital works except those that are committed such as the SSR resignalling and keeping the Central and Bakerloo fleets limping along.
Railway Gazette commented in an article 2 days ago that TfL would separately be seeking “private finance” for this new DLR fleet so it’s looking likely it won’t even own the future fleet. Similarly the contract structure is for new train supply and a 35 year long maintenance contract. In short this all being paid for on the “never never” via the revenue budget and not capital (assuming TfL can organise a finance deal that is affordable). That says something to me about the likely parlous state of TfL finances come 2020.
I also think the budget is one reason for this work slipping sideways but so if reviewing strategy to push things out of the current Mayoral term as far as possible. Yes there are all the practical and engineering issues you cite but I just think TfL can’t afford this in the short term. We are surely also heading to the same place with the extra stock for the Northern and Jubilee Lines – complete radio silence there and the election won’t have helped matters by delaying relevant approval meetings. I have a sneaking suspicion that Crossrail will be cited as the reason for delaying expenditure on more Jubilee Line trains. It’s only the Northern where something has to be done to cope with the Battersea extension.
Anyone know if/when Royal Albert’s platform will be upgraded for 3-cars? I’m guessing a long way off with TfL’s budget cuts. It has seen a few hotels open in the past couple of years and Asian Business Park (now underway?) will accelerate growth.
The photo titled “Early testing on the DLR at Devon’s Road.”
On the version I see, I’m seeing a BR DMU (a cravens unit?). The sort that used to operate the (truly dire) service to North Woolwich
“Note that a whole year is allowed for in the schedule for pre-revenue testing and training using the first three trains”
Do we know how it is planned to do this? At an off site facility? (Wildenwrath? Old Dalby?) Or on the DLR itself overnight when there are (currently) no services? Or to be slotted in between existing “in revenue” services?
I have lived with the DLR from day one – I moved to the Isle of Dogs one week before the DLR opened. My recollection is that the worst hiccups have always been with the radio/computer signalling interface. In the early days it was routine for the entire system to screech to a halt as the central computer “lost sight” of all trains. The “captain” (as they used to be called, with their garish McDonalds type uniform) had to radio in the position of each train to central control for it to be manually reentered into the system – my personal worst was 40 minutes trapped between stations before the computers could be kicked back into life.
In terms of passenger growth on the DLR. This model is a great way to visualise the astonishing number of high rise residential developments planned or underway on the Isle of Dogs. Most of the new developments on this diagram are already under construction.
http://www.isleofdogsforum.org.uk/3d-model-pictures.html
@ Island Dweller – that 3D model is moderately terrifying. How on earth can such a small area sustain that sort of development? The transport network certainly won’t cope with it. Roads won’t cope and rail is already overloaded and Crossrail will only assist short term before that’s in trouble. Do the politicians in Tower Hamlets understand what they are doing in approving this scale of change?
A few comments on the article….
“Non-standard too, at the time, were side-mounted cameras with displays in the driver’s cab, so that the train could be Driver Only Operated (DOO).”
Did the Southern 377s already have body side cameras by then?
“Early testing on the DLR at Devon’s Road.”
As already mentioned, the train shown isn’t a DLR unit. I seem to remember a DLR handbook (Capital Transport publishing?) mentioning that a BR unit was run over the still then BR tracks to test noise levels in the flats/houses that had been built over/across the Poplar – Bow line during the DLR planning stages.
“Plant Engineer reports that DLR trains are undergoing extensive works offsite.”
Doesn’t it suggest that it’s the bogies that are undergoing offsite works?
In the link on District Dave’s forum, I posted the link to the TfL procurement website. The document on the TfL procurement website is an slightly abridged version of what eventually went on to the OJEU TED website. The OJEU TED link is http://ted.europa.eu/udl?uri=TED:NOTICE:185720-2017:TEXT:EN:HTML
The OJEU TED document also mentions “In addition, DLRL may require the disposal, in a sustainable manner, of the existing DLR rolling stock fleet consisting of up to 94 vehicles.”
Simon
@WalthamstowWriter. “Do the politicians in Tower Hamlets understand what they are doing in approving this scale of change?”
We’re edging into politics but I hope this is allowed because this scale of development is extremely relevant to transport provision. My thoughts.
(1) Remember that LB Tower Hamlets has (until recently) been massively dysfunctional under the Rahman regime, with government appointees required to try to restore order. Normal political scrutiny just ceased to exist for a while. The government appointees have admitted that they are struggling to get the council functioning again because many processes have been comprehensively broken (perhaps akin to Railtrack throwing away years of accumulated corporate knowledge).
(2) Even if LB Tower Hamlets try to refuse a scheme, most big developments get through on appeal to the Mayor. Developers run rings around planners – the system is now massively stacked in favour of development, however out of scale a proposal is.
(3) There is some local backlash to the overdevelopment. That 3D model was not produced by the council – it was produced by a local residents forum – they had to do it because no one else was looking at the bigger picture and understanding the scale of what is happening.
Re your comments about infrastructure. You missed out
(1) Water – the mains under the Westferry Road repeatedly bursts because Thames Water keep pushing the pressure up to try and feed all the new development – but the old pipes can’t take more pressure. Again, a refusal to look at the bigger picture, Thames Water insist these are individual bursts and not part of a pattern (my local councillor is fighting them about this).
(2) School places (3) Doctors surgeries. The list goes on….
ID & others
The problem is particularly acute in LBTH, for the reasons you have stated, but …..
The same is happening, as far as I can see, across most of the Boroughs.
I know LBWF are pushing the “development” of ridiculously large numbers of new dwellings, with no apparent space to put them in, nor any real thought as to the transport & other utility provisions, never mind the other essential public services you mentioned.
It might be interesting to hear from other parts of London as to what is happening in their “parishes” ??
Dare I mention the acronym “CR2” in this context, too?
Royal Albert DLR station is not that busy.
Platform extensions on the viaduct are quite expensive.
The scope for a Bakerloo branch to Canary Wharf (South Dock), coming off the Lewisham extension near Old Kent Road no.1 station, was reviewed last year by various parties. The Jubilee Line was expected to face worsening levels of crowding beyond Crossrail’s immediate congestion relief.
The Bakerloo scheme was to relieve the Jubilee Line, and address large scale extra housing south of Heron Quays foreseeable during the next two decades, within the Isle of Dogs Opportunity Area. The tube might have continued towards Millennium Village and Charlton Riverside, which are also priority housing areas.
It was concluded that there was a fine line (sic) between the Bakerloo Line being able to accommodate two branches or just one major route beyond Elephant & Castle. In the absence of any additional long term railway, there will be greater capacity pressure on DLR, and on Crossrail to expand its own capacity by means of higher frequency and longer trains.
Island Dweller
The diesel unit pictured was trundled down the NLR towards the Isle of Dogs in the early 80s,partly to test noise intrusion to flats built alongside and above the line,and as a publicity move to promote the idea of re-opening the line to passenger traffic.This was around the time,one recalls,that the service from Camden Rd to North Woolwich was inaugurated,and it was thought that a similar service could be usefuly run to Docklands.
A missed opportunity,imho.
Slugabed. Ah – thanks for that – now I see what is meant.
So perhaps a better caption would be “noise testing run pre DLR”.
The initial cars on both the Tyne & Wear Metro and the DLR (and indeed Manchester Metrolink) were built around the standard dimensions of the German Stadtbahn B car, although both avoided the degree of cab end taper needed to fit existing systems.DLR cras from the B stock onwards are a little narrower in the body (2.55m instead of 2.65m if I recall correctly) in order to allow simple externally-hung sliding doors without having to adjust the platform nosing stones. I believed this was a mistake at the time, causing an admittedly small decrease in capacity for ever more.
I suspect therefore that the replacement stock for both systems could be of the same basic design which would give a benefit to the manufacturer winning the contract for whichever is awarded first. As with almost any stock in the light rail field, there will be many common components and sub-systems that will be used in what may be a relatively bespoke configuration. The curvature, for example, is certainly not unusual in light rail (if I distinguish these in this instance from tramway) applications.
@ Island Dweller – thanks for the update and kudos to the residents who developed that website and visuals. I was thinking mostly from the transport perspective but part of me was wondering whether the Isle of Dogs could actually take all the piling and foundations of those enormous buildings. There must also, at some point, be weather and wind related implications given the way cold and wind is chanelled up the Thames at times. So many tower blocks in a confined area could create a really horrible environment in terms of natural light and wind “whip round” where towers are concentrated.
The other aspect was the combined effect we are now seeing – Isle of Dogs, Royal Docks, Greenwich Peninsula, Canada Water / Rotherhithe, Deptford – Woolwich by the riverside. There is a tremendous scale of development very near the river which is going to cause tremendous transport issues in and between those localities as well as to / from the main employment centres. It’s the combined effect that I find really worrying in terms of the rail, tube and DLR infrastructure. Bus services are another story altogether and they have their own set of nightmares in this part of the world. We must see what the Mayor’s Transport Strategy and London Plan updates have to say about all of this.
Government policy appears to be so focussed in on the need to provide a lot more housing (without a significant increase in public expenditure) that the development system has been skewed so as to make it quite difficult to refuse consent for new housing. One of the consequences of this has been that planning of complementary infrastructure (in the widest sense) planning has all but been abandoned outside what the Mayor and GLA are doing in London (and what the metro mayors in Manchester, Liverpool, West Midlands, et al are expected to do there). This can be seen, for example, in schools provision, where the growth resources are primarily directed at free schools, which are established where the promoters want, rather than where there is a population growth. Outside London we are seeing relatively large housing developments (>50 dwellings) in rural areas without any health, education, retail or transport provision associated. The potential fall out is quite frightening.
“Quite difficult to refuse consent for new housing”
Are you serious? Planning committees refuse applications every week due to pressure from those satisfied with their individual housing circumstances!
Thankfully London has had Mayors prepared to override local nimby objections!
Yes FlippyFF, Southern were using 377s with body side cameras on DOO routes for years before LOROL started. Though if you read certain articles in both the mass and trade press you’d think DOO only began last year. A BBC journalist started one of his articles “There are door controls in the driver’s cabs that have never been touched.” Worrying that they can’t even get such vital details right.
@Patrickov
Because the 92 stock on the Central is in a worse state than the Bakerloo stock, despite being newer.
Because the 92 stock was not designed to be driven by hand, it was designed to be driven by computer when the driver has closed the doors and pressed the go buttons. The modifications (e.g. mods to electric pick-up shoes) required for the 92 stock to work on Bakerloo would be immense, you may as well buy new trains.
The Picc stock is also in desperate need of replacement too. The Northern and Jubilee trains are also designed for auto computer driving, so they wouldn’t work on Bakerloo either. Basically Picc and Bakerloo need to be resignalled for auto driving and NTfL purchase needs to get a move on arriving, because overall Central, Picc and B’loo need new trains. the Northern and Jubilee need extra trains.
The capital expenditure for these planned programmes keeps getting shifted back, because some politicians keep reducing TfL funding!!
@Patrickov
Because old is not necessarily worse than new. Which is why Scotrail are planning to take on 1970s HSTs replacing newer class 156/158/170 dmus from the 1980s/90s, whilst First MTR plan to replace SWT’s class 458s (from the late 1990s) and class 707s (not yet in service!) but are taking on 1980s class 442s.
Depsite the lengthy prototyping (1986 stock), the 1992 stock was built down to a price and has been very troublesome in service. Despite its age, 1972 stock is still more reliable, and what is wrong with them is easier to fix.
@Stuart Matheson
I said difficult, not impossible. But, of course, it’s very easy for a local council to support vociferous local residents in the clear knowledge that their refusal will be overturned by the Mayor. That’s politics for you!
Essen is keeping the original DLR trains until at least 2025.
From https://www.waz.de/staedte/essen/evag-bleibt-grossreparatur-der-u-bahnen-in-essen-erspart-id210608537.html:
New trains are coming in eight years
Evag has almost no replacement trains anymore. And it is only next year that the transport company begins to create a specifications for its new trains, and will then go to tender at a later time. But there are several years left until production and acceptance.
The first new underground trains in Essen’s rail network can enter service at the earliest in 2025. The old trains still have to last. For the investment in the new fleet in three-digit millions, Evag wants to take out a loan.
Two comments:
The Class 377 electrostars had body side DOO cameras years before the Class 378s appeared
DfT conceived the IET
Here, courtesy of Thames News, is a 4-minute video covering how the DLR started, its early difficulties and extension to Bank, then under construction:
https://www.youtube.com/watch?v=b9oJHlAjR_A
Fred: I think it was the IEP that was conceived by the DfT. The IET is the Institution of Engineering and Technology, formally known as the Institution of Electical Engineers (IEE)
Apologies for not have replied sooner to various comments.
To kick things off with some comments from 19th May…
100andthirty,
Putting it like that the S stock had a very long introduction period. I was unaware of what was happening behind the scenes during PPP. I thought it was all talk at that stage. Looking at the introduction as a whole then the period does seem extraordinarily long. However, in my mind I was thinking of a line-by-line basis and the implementation seemed to go relatively smoothly. The fact that LU chose to hold on to some District line trains after the last S stock had been delivered should not count against a successful delivery and introduction into service of the stock.
Tyteen 403,
Four-car trains has been looked at and found to be hopelessly bad value for money. Basically a lot expensive upgrade work. This would possibly including strengthening viaducts as well as some problematic platform extensions (Bank, Tower Gateway, Woolwich Arsenal, possibly Lewisham even). Cutty Sark station would probably have to be closed. The money would be better spent on alternatives.
What you may have seen is a two-car train at Beckton and assumed it is a three-car train. You would not have been the first person to make this mistake and jump to the wrong conclusion.
Moogal, Ed,
Royal Albert station is only two-cars long because it is lightly used and on a viaduct which makes it expensive to extend. I suspect, even at the time, the attitude was that, as it was not really currently needed, it will only be extended when a developer pays for it – which is what will happen with the Associated British Ports development.
Walthamstow Writer,
I avoided writing about details of financing as the article was long enough as it was and I guessed you would comment on it! Basically, the warning signs are there. The hint of a suggestion that things didn’t happen sooner because there was no money. Then recognition there still isn’t money in the budget but it is really imperative to get on with it. So we have this undesirable situation where the trains will be leased but then bought when the money can be found. To me, this is really a recognition that leasing is not a good deal in this case but there is no alternative because of lack of forward prudent financial planning. And the Mayor’s fare freeze doesn’t help but we can’t blame everything on this whenever there is a budget issue. Having increasing fares would only have raised so much and can’t be expected to pay for all the projects with financial problems.
Island DwellerFred,I was very careful not to claim and not to state that class 378s were the first UK trains to have side mounted cameras. They were still novel and I suspect that Southern either hadn’t then used them in conjunction with the drivers closing the doors or, if they had, their usage was light and not extensively tested.
When class 378s were introduced they had tremendous problems with the software related to drivers closing the doors which Bombardier seemed initially reluctant or incapable of fixing. The reason this problem existed was in part because the use of it was novel. This was not a well-established product at the time of introduction – which was the point I was making.
Jonathan Roberts,
The idea of extending the Bakerloo from Old Kent Road to Docklands beggars belief to me. I find it incredible it was suggested.
First, if capacity from central London to Docklands really is an issue after Crossrail then surely far better to spend the money removing the Shenfield branch of Crossrail and connect it so something else – thus allowing 24tph on Crossrail to serve Canary Wharf. Basically, make the most of what you have got, not provide another half-baked, half-capacity new option.
Note: Suggestions as where to extend the Shenfield line in such a scenario not wanted.
Second, as surely the Bakerloo line history should have taught us, it is a major long term error to branch out from a tube line too close to central London. It took about 40 years for the first mistake of this nature on the Bakerloo line to be rectified. We don’t want to do it again at the southern end.
In defence to those who made the original decision for the Bakerloo line to diverge at Baker Street, it did at least overcome an even worse proliferation of branches on the Metropolitan line and increase capacity between Finchley Road and Baker Street where it was much needed.
Fred,
The IEP may have been conceived by the DfT, I am not disputing that, but the design is now one that Hitachi are offering as a product. They are also willing to modify the design to handle different requirements. Until the IEP was commissioned Hitachi had no off-the-shelf option available for the requirements (as perceived by the DfT) for high speed train travel in the UK. Now, with the product here, they can quote short lead times for new orders.
Southern WERE extensively using 377s with body side cameras and had been for years when the 378s appeared. On all the routes which were already DOO then in fact. Staff were doing platform dispatch on 378 introduction and there was much surprise from Southern drivers that a system they had been using for years could be so different and have issue on another TOC’s trains.
@PoP. Body mounted cameras. I think you meant to reply to Fred,
Island Dweller,
Sorry, wires crossed. I meant to reply to you on the issue of testing. I don’t know but presume that they must be tested on the DLR network. It shouldn’t be hard. There is Beckton depot and all the DLR is bi-directional so they could simply create a short virtual test track on one of the branches with longish intervals between trains, if needed. Besides, they would really want to test on the harsh DLR features such as some of the very tight bends that probably all have different profiles. Conversely, there is the straight fast section under the Thames to Woolwich Arsenal where currently the ride is appalling as you get “hunting”.
No doubt there will also be the usual evacuation exercises to make sure that nothing in the new trains creates a new problem in an emergency and these can only sensibly be done at real-life locations.
100 and 30
Re IET – ‘formally’ or ‘formerly’?
LITTLEJOHN. indeed – formerly – I have been caught out when making a pedantic point!
@RNHJ: Surely nosing stones can be adjusted without affecting accessibility too much?
Is this what the announcement in the budget yesterday related to, or something else?
@Herned? What announcement? Link?
Point 5.11 says:
£291 million from the Housing Infrastructure Fund, funded by the NPIF, to unlock 18,000 new homes in East London through improvements to the Docklands Light Railway
Tom Edwards on the BBC has a small item about this.
https://www.bbc.co.uk/news/uk-england-london-46034974
He suggests it is redevelopment of the Poplar depot (for housing) and construction of the Thames Wharf station (west Silvertown area).
There is also the suggestion of new trains and an expansion of Beckton depot (presumably to make up for the loss of Poplar, as well as the new trains)
Timbeau……I am sure we have covered both new trains and Beckton depot expansion to look after them on here in the last 18 months. In brief. 44 new trains, 88m long. Tenders being evaluated as this is being written.
@130
I’m sure we have, but the BBC article only mentions 14 trains. Are these some of, additional to, or instead of, the 44 previously mentioned?
Asian Business Port at Royal Albert Dock, not Associated British Ports.
@ Island Dweller
Thanks for the link. Still not sure how that will provide 19,000 homes, but a minister said it so it must be true
Timbeau……The original plan – in the public domain via the usual published TfL papers – was to buy 44 trains which would allow a) all trains to be 3-car length and replace all the “B” type. The nominal increase in fleet size of 10 trains. If they have any sense, they will have included options for a lot more trains in the invitation to tender. The logical thing to do would be to include options to increase the fleet size further and to replace the 2007 trains. thus if the 10 extra trains became 14, then they’d have the possibility to call off from the contract.
I’m not saying there’s any money to do these things, but if you don’t have the options you end up having to tender again and public procurement is painful!
There is already planning permission granted for 19000 new homes on the Isle of Dogs (the Poplar DLR depot is at the top end of the island). Add in projects in the pipeline and this figure goes to 36,000. So adding a further 19,000 homes isn’t perhaps as ludicrous as it appears.
Example – The Spire building (site of former Hertsmere House, a short walk from the new Crossrail and the existing West India Quay stations), will be the tallest residential building in western Europe. 241 meters, with 861 units.
The housing density on the Isle of Dogs is now denser than Manhattan – something many people don’t appreciate if they haven’t visited for a few years.
@130
The original article does indeed say the ITT is for 43 (not 44) units with options for up to 34 more.
Tonneau……thanks for checking!
@ IslandDweller
Fair enough, it is quite astonishing how much has gone up in the last few years, especially on the South Quay side.
This is why Canary Wharf was looking at Bakerloo branch options the other year, to Canary (and Charlton) via the South Dock, as well as to Lewisham.
Timbeau…….caught out by my tablet spell check again……Tonneou indeed!
One of the councillors representing a ward on the Isle of Dogs (Andrew Wood) has published the reply to his freedom of information request – concerning how DLR capacity on the Isle of Dogs will be increased.
Link to what he had published below.
https://www.facebook.com/groups/1458438024296291/permalink/2392910544182363/
Order announced on 12 June with CAF. They will be five-car trains, which surprises me a bit as presumably each car will be slightly longer than the existing ones.
Yes, they will have to be if by ‘bigger’ TfL is saying the trains will be longer. Does anyone know what work went into determining the larger possible bogie centres?
It seems to me that current DLR 3 X articulated unit train will be replaced by 5 X conventional cars, making similar length, with similar inter-bogey length, and car-end overhangs. Current 9-bogey train replaced by 10 bogey train.
Please, please…
The spelling is *bogie*
Please!
I guess they would need to move to standard cars rather than articulated to keep the bogie centres the same. 3.5m is quite a lot longer though, I’m surprised there aren’t issues with overhang on the sharpest corners
Wikipedia managed to really confuse on Friday night, as “car” can mean the articulated pair or each vehicle and I’d calculated that these new cars were over 30m long!
However, I have since found a drawing of the B07 stock here.
There’s 4m overhang at the front and back of each pair, and I guess all is ok if this is not exceeded on the new longer carriages.
Edgepedia: a 4m overhang between cars is definitely not OK if there are to be wide open gangways. If this overhang is provided between intermediate cars, the relative movements between cars on reverse curves will be large. This is hard to accommodate with a gangway.
Current 3-unit DLR train is about 84 metres long. 5-car train with same end overhang and inter-bogie distances, but inner ends same as S stock totals 79.6 metres, or 4.4 metres shorter. DLR curves are tighter than sub-surface lines, so maybe gangway narrower or inner ends even shorter. Anyhow, looks like inter-bogie distance may be up by almost a metre at least. PS: S stock inner-ends of cab cars are 750mm longer than others! Anyone notice any difference in the ride?
I really do hope they have thoroughly checked that those overhangs & curvature-alignments are capable of fitting round the tight curves of the DLR & that the new-layout internal gangwaying will actually work! It could be a very expensive mistake if they don’t.
Personally, I think abandoning articulation is a big mistake, as it guarantees a good internal gangway, as on the present stock, as well as fewer moving parts & lower weights. But we will have to see, won’t we?
Apparently CAF deemed it unnecessary given the specification of TfL (or whoever wrote the specification.) They have built many trains and metros with Jacobs bogies (I think this is the type of articulation you’re referring to) outside the UK.
I will for now assume the specifications passed to CAF where correct. However that is a dangerous assumption as I do remember an incident about 10-15 years ago where tens of platforms had to be heightened in the Netherlands because somebody had passed the wrong platform specifications to Stadler for a train with ‘step-free’ entry.
Albert J.P.
And the Piccadilly line trains that scraped the tunnels, a few years ago ….
Greg Tingey,
I have had many arguments with Graham Feakins over the Piccadilly issue. The trains were specified correctly but five of them (including, unfortunately, the very first one to take to Piccadilly metals) turned out to be out of specification. Because the trains were longer than the previous generation of stock many spurious claims were made about the trains being built to incorrect dimensions.
The significant point is that it was resolved by the manufacturer agreeing to pay for the necessary ‘easement’ of the tunnels at various critical points which rather suggests where the blame lies.
Science and manufacturing have moved on since the 1970s. In particular the ability to map an exact profile (especially of tunnels) extremely accurately at every point using lasers means there is very little excuse for anything being built outside the appropriate loading gauge. Moreover, for better or worse, trains are built to far more detailed tolerances these days. If one is within specification they will all be within specification – or vice versa.
@Albert JP
I don’t recall that – there were out-of-gauge problems with a new fleet in France about five years ago though.
https://www.theguardian.com/world/2014/may/21/french-railway-operator-sncf-orders-trains-too-big
Your mention of Jacobs bogies has puzzled me. How does that reconcile with previous comments that the new units will not be articulated? (e.g Greg’s comment immediately before yours, and other by Taz and Herned)
The Picc trains couldn’t have been so large, as one later transferred to/from Hainault for testing via Caxton Curve west of Shepherd’s Bush, the tightest curve on the system, albeit out of traffic hours.
@Timbeau
I read the comment as CAF are well aware of the technology but haven’t used it as it’s not a requirement.
timbeau,
I recall that the main problem was the reverse (‘S’) curve at South Kensington. Basically a seven-car train was replaced by a similar length six-car train.
Was it not the roof in the middle of cars being too high because the steel underframe wasnt as flexible as supposed under body load? Something about countersunk rivets… Or was that the 83ts batch one?
Just to echo another point though; “few years” – try “almost half a century ago, in the previous millennium”. It was closer to a few years ago that the gauging test for the 09ts failed in the same area.
Do agree with Greg on the issue of articulation sharing a common bogie. From Taz’s suggestion it would appear the DLR is on course to receive shorter trains with fewer doors. Not good.
@Herned yes that’s what I intended.
@Timbeau, that was Arriva in the north of the Netherlands. I can’t find much details on the web, but it appears that the mistake was discovered (and reported by a few local newspapers) in 2006 and I found some forum posts that indicated platforms in the province of Groningen were heightened in 2008.
@ Ben
The trains are going to be 87m long, slightly longer than existing 3/6 (depending on how you look at them) car sets. Hopefully the designers will put in 3 doors per car, which would be an increase in the number of doors, but that’s speculation on my part
@Herned
The artist’s impression appears to have two pairs of doors in the first car and three in the next.
https://www.railengineer.co.uk/2019/06/12/caf-wins-dlr-train-order/
The sharp curves on the DLR are notable. Sit in an inner end seat facing the next coupled car as you go over the pointwork from Poplar, through the Delta Junction and then over the points to the centre platform at Canary Wharf and you will see how much the cars swing relative to one another. The coupler moves from straight in line to more than a 45 degree angle, and over reverse curve crossovers moves in a couple of seconds from one extreme to the opposite. You could never have a wide gangway between the cars. At the time the new 2012 trains weer ordered I did hear that inserting a centre section (discussed above) to make each unit 3 sections was not possible because of this. So I wonder how the new trains are going to do it.
Mr Beckton – If you view the DLR vehicles as trams (as they are), rather than trains passing through sharp curves, then I think you will have the answer. See this clip for an example of a 3+ section tram with wide gangways (1 min. in):
https://www.youtube.com/watch?v=I-w0l-u2Tss
Reverse curves are also no problem. Everything just follows through. The coupling is basically a turntable linking the floors between the cars.
P.S. The noise of the wretched ventilation system and even the traction equipment in that clip totally negates the huge achievements of the tram manufacturer Düwag and others in the 1960’s onwards, which produced trams that were almost completely silent by comparison. I noticed that problem first on the Newcastle Metro in the 1970’s, with cars built by Düwag but with blasted noisy interior fans (British built) that destroyed the attraction of ‘silent’ traction kit.
@ PoP 18 Jun at 14:29 – Since you mention my name, yes, it was indeed the reverse curve approaching South Kensington and, as reported to me the morning after by an LTE employee, “not only did the sides get bashed in but also the roof” (because of the tunnel line dipping in the vertical plane, as almost suggested by Ben above). All this and more was confirmed to me some years later by the Deputy Chief Civil Engineer of the Underground.
Whether or not it was the fault of the manufacturer, somebody hadn’t done their sums and it was too late to modify the stock that had already been delivered from the manufacturers to West Ruislip for fitting out, so the tunnel linings had to be widened out where necessary.
I’d already brought up this prospect when I viewed the mock-up at Acton Works some years earlier and I’d drawn their attention particularly to a possible problem at South Ken, knowing those sharp curves as I did. My comment was dismissed…
Graham Feakins…..the Newcastle cars were built by Metro Cammell with GEC equipment. The bogies might have been by Duewag, but that’s all.
And as to gauge clearance, what was need stated about 1973 tube stock and hitting tunnels was which was wrong. In fact it was both. The 1973 tube stock was slightly larger than intended, but some of the tunnel, mentioned above, also infringed the gauge. In a system as tight as the tube, if there are a few tunnel constraints that would result in the new train being smaller inside than its predecessor, it is sensible to fix the tunnel. Otherwise, over a few generations, London would get its equivalent of the Hungarian Children’s Railway, as they would be the only people who would fit!
With today’s technology, gauging predictions and tunnel measurements are much more accurate………he says hopefully!
@ Graham Feakins
Isn’t that tram similar to this? https://de.wikipedia.org/wiki/Variobahn#/media/Datei:OEG_Variobahn.jpeg
The segments are articulated and some have no bogies under them, so there two joints between each bogie. Something like that would be absolutely fine on the DLR, it seems odd to me and others that trains with normal bogies at each end of the car would work as well. On the current DLR trains it is very obvious that there is much more movement between the units than internally, as a result of the overhang of the ends of the cars. I’m sure they have thought of all this though!
This photo on the Wiki of Croydon’s Variobahn
https://upload.wikimedia.org/wikipedia/commons/thumb/a/a7/Au_Morandarte_Flickr_Tramlink_2558_on_Route_1%2C_East_Croydon_%289756077682%29.jpg/800px-Au_Morandarte_Flickr_Tramlink_2558_on_Route_1%2C_East_Croydon_%289756077682%29.jpg
@ 100andthirty – You’re quite right of course about the Tyne and Wear Metro cars (thanks for reminding me) but it was indeed Düwag who provided the quiet-running traction kit and bogies and GEC who installed the noisy bits, basically I surmised at the time because they weren’t then used to any quiet electric traction motors over here and therefore ‘nobody would notice their own noisy kit’. I wouldn’t dare blame MetroCam… but my, how I was shocked and embarrassed I was at the tremendous racket when I first heard a Vic Line train of ’67 Stock roar into a station!
P.S. Slight correction re Tyne and Wear – some bits were built under licence from Düwag in Germany.
@taz
“The Picc trains couldn’t have been so large, as one later transferred to/from Hainault for testing via Caxton Curve west of Shepherd’s Bush, the tightest curve on the system, albeit out of traffic hours.”
It is not jus the tightness of the curve, but the dimensions of the tunnel, that are relevant. Tunnel diameters on curves have to be wider than on straight track, to accommodate throwover. If the Caxton curve tunnel was more generously-dimensioned than the Brompton Road ones, there would not have been a problem there.
A friend who worked on the project told me that when they surveyed the Central Line tunnels to ensure the then-new 1992 stock would fit, they discovered that at some points the tunnels marginally breached the dynamic envelope for the existing 1962 stock! He didn’t say whether this was due to errors in their original construction, or ground movements during the following 90 years.
There is one 1973 tube stock car – the Track Recording Vehicle, that routinely operates over the whole railway including the tightest parts of the Central line. As a minor concession to gauging, the heights were set a bit low simply because the car didn’t have to accommodate a crush load.
Well I’m sure we all hope that CAF know what they are doing. The DLR has never had any bogie vehicles, only Jacobs Bogie articulated cars (a DuWag, now Siemens, patent I believe). Others can use this design, but have to pay Siemens royalties. If anyone can point to bogie sets with full-width passenger gangways being used on curvature as tight as the DLR, please do post.
The curve at Bastille station on Paris Ligne 1 is 40m, the trains there are normal bogies with full width gangways. From aerial photos I don’t think the DLR curves are quite that tight, but that’s not going to be particularly accurate. The difference is the Paris trains are about the same length but have one more car so the angle between each one will be smaller
As other comments have made clear, whether a particular design of train can operate safely on a particular line is not just a matter of how “tight” the curves are. The exact shape of the cars, and the exact shape of the available space (whether tunnel, or swept obstacle-free area of an above-ground section) are all relevant, as are the suspension characteristics, the train speeds, and the exact profile of the track (horizontal and vertical), including whatever transitions exist into and out of curves. This latter point may be particularly relevant to full-width-gangway stock. Conventional non-Jacobs bogies and sharp reverse curves produces mental ripping noises in my head, but these noises could be quite spurious if the reverse curves actually have reasonable transitions (and I rather expect they do, if only for passenger comfort reasons – a ride on the DLR may look a bit like a ride on Steel Stella, but to me it does not feel at all similar).
@MALCOLM
Thus, Docklands Light Rollercoaster.
There are indeed tight curves on the Paris Metro, but I have always been struck by the appearance of Metro vehicles, which seem to have the bogies as close as possible to the ends of the cars. (pneumatic MP05 and steel wheel MF01 stocks shown in the links below) This minimises throwover, (an advantage at places like Bastille) and this in turn also means that car ends are relatively closely aligned even on reverse curves.
http://www.djibnet.com/photo/mp05/intercirculation-du-mp-05-3972077093.html
https://upload.wikimedia.org/wikipedia/commons/7/74/Attelage_MF_2000.jpg
Tonneau…… These photos show the gangway which is exceptionally long, and, recalling my last trips to Paris, not a nice place to stand, partly due to lack of light and partly because of “bucking bronco” motion though one’s feet.
Current DLR and S stock gangway areas are OK places to stand. On the former, one only has to adjust one’s position as the train goes round curves. On the latter, one can easily stand on the solid floor of both cars, or right on the end of one of them. One never has to stand on the gangway floor itself.
Re. DLRollercoaster – Hopefully they will finally do away with the extreme hunting oscillation with the new stock. It surprises me that some form of damping mechanism wasn’t retrofitted to mitigate the vexing wibble-wobbles earlier.
I believe the hunting is a feature of the wheel profile, which itself is designed to negotiate those tight curves on crossovers without the flanges jamming. Worst place is between Royal Albert and Prince Regent on the Beckton line, coming downhill from the high bridge.
Timbeau… Sorry referring to you as Tonneau……my tablet’s spell checker attacked me again. Id got rid of all the madness from the text but missed your “handle”.
NickBXN… That they have failed to tame the oscillation is not for the want of trying. It’s not helped by the fact that the oscillation “imprints” asymmetric wear on the track.
Mr Beckton… The wheel profile is intended to minimise squeal on some of the sharper curves. It will be flange design that prevents jamming on “those tight curves on crossovers”. More generally, operating on the tight curves is always a challenge even with coned wheels. On a conventional railway, flange contact is inevitable on curves with a smaller radius than 400 m. DLR gets down to 40 m and no amount of coning will prevent flange contact. There will always be some stick-slip which will lead to noise. It is even more challenging on the B90 stock where there is one motor on motor bogies driving both axles. They did experiment for a while on the former delta junction to the north of West India Quay by spraying the rails with water.
Have they considered ordering tilting stock for those tight curves? (Only joking.)
@Alex: Perhaps they should consider Talgo technology?
Positioning the bogie – and more significantly its centre of rotation – nearer to the ends of a car incurs the disadvantage of increasing the centre-throw at the middle of the car, which will be greater than the end-throw, as evidenced in “mind the gap” scenarios.
In terms of ride quality, articulation always seems to be the winner … as long-ago personal experience & the accounts of other travellers, long before me testify.
The trouble is that articulated vehicles can be & often are more expensive to maintain. (note) but they “hold the road” better, give a smoother ride & are usually less-prone to catastrophic failure in derailments ( See also the Castlecary crash in Scotland, which was bad, but could have been so much worse ).
In terms of carriages designed for lines with tight curves, like the DLR, the current system with a circular “pad” adjoining the fixed sections in each coach gives pasengers, especially standees, an easy transition. I’m really not so certain or happy about the proposed layout.
( Note: I am, of course referring to the Gresley bogie as used in GNR & LNER articulated stock – it gave a superb ride, not equalled until the BR4 (?) bogie came along … but oh dear was it maintenance-hungry & by modern standards expensive to keep in operation in terms of trained mechanic/engineers time costs. )
I believe that all DLR platforms are straight, thus “mind the gap” does not apply.
Hunting is a particular hobby-horse of mine, so apologies for delving into it here perhaps a little too deeply for some. However . . .
The problem was successfully addressed by the Metropolitan Electric Tramways (MET, part of the Underground Group) in 1930 when tramway services in North London were being accelerated to better compete with buses. Nigel (later Sir Nigel) Gresley was accelerating train services on the Great Northern Railway nearby at the same time, speed being very fashionable then. The MET’s initiatives included powerful motors with auto weak field (equivalent to overdrive on cars), lineswitches to cope with heavier currents, air brakes, passenger flow, auto air doors, efficient interchanges with the tube (at Manor House and Finsbury Park) and (for image’s sake at least) a hint of streamlining.
Elimination of hunting at speed was addressed successfully on centre-entrance car 331, the final experimental Feltham, now preserved in operation at the National Tramway Museum, Crich. Instead of having bearer pads at the ends of the bolsters on which the body sat, 331 had rollers. The quadrant plates on which they ran under the body had very shallow indentations into which the rollers registered in the straight-ahead position, locking the trucks (bogies) and absolutely preventing any hunting or lateral oscillation at speed. At curves and at pointwork, the rollers easily disengaged from the shallow indentations and then greatly eased the rotation of the bogies as they negotiated the curve(s).
It is evident, because there was no provision for lubrication, that the MET was trying out the roller concept on what were after all entirely experimental trucks. By the time 331 was sold on to Sunderland in 1937, the (forgotten about?) rollers had worn on their plain dry steel-on-steel bearings so badly that they “sat down” in their trunnions and wouldn’t revolve. They jammed solid and gave the car a reputation, which 331 brought with it all the way to Crich and displayed during shunting, for derailing at facing points as well as rapidly wearing away its flanges.
When I undertook the mechanical and electrical restoration of 331 in 1972-3, to demonstrate its operational viability, new bolster rollers with greasing facilities were made and fitted. The car behaved beautifully with its new rollers, giving a wonderfully smooth steady ride at full speed and negotiating the tortuous depot pointwork magnificently.
Sadly, many years later when 331’s restoration was completed, the workshop regimen replaced the rollers with conventional bearer blocks. The auto weak field contactors and the auto air doors were also omitted. That loss to posterity of key parts of 331’s raison d’etre raises questions of curatorial ethics which I won’t go into here, except to say that I consider it a deplorable example of dumbing-down.
Thus hunting was successfully addressed some 90 years ago, by the MET in North London. London Transport was formed shortly afterwards, curtailing tramway modernisation, regulating transport provision and diminishing the competitiveness which had driven such dramatic progress in tramway technology (the same could be said of “Bluebird”, LCC’s “Tramcar of 1932”, soon to enter service as LCC No1 at Crich). And what about hunting today?
I haven’t experienced any disturbance on the DLR which is anything like as bad as the dramatically violent lateral oscillation at speed which occurs on parts of Manchester’s Metrolink system. Most of Manchester’s trams do it to some degree, especially in places where the maximum line speed of 50mph theoretically applies. It’s particularly noticeable on the Altrincham line inbound between Stretford and Old Trafford, and in several other locations, resulting in severe speed reductions. I’ve filmed quivering articulations on many occasions. It’s an extremely ugly and rather frightening phenomenon.
I strongly suspect that the cause is the system’s mixture of inclined and vertical rail. The grooved tram rail used in the streets is installed vertically. The rail on the “railway” sections is inclined inwards. The tram wheels are coned to match the inclined railway rails, so that the “running band” (line of contact) lies in the centre of the rail head. “Steering” at speed is achieved by the coning. Fast trains have yaw dampers to control hunting, which unless switchable would derail a tram at points or on entering sharp curves, especially some of the completely un-transitioned horrors. Reminder – the MET had a solution in 1930 (see above).
When (non-tramway) contractors installed the first grooved rails in the centre of Manchester in 1990, they tried to install them inclined inwards to match the “railway” coning of the tram wheels. That wasn’t too difficult on straight track, but two months were wasted trying to carry the inward inclination through sharp curves (try it with a desk ruler). In the end they installed the tram rails vertically, and then surface-ground them to match the “railway” coning.
All subsequent grooved tramway rail has been installed vertically with no grinding. This means that the running band lies adjacent to the gauge corner, as can be seen clearly on relatively new rail. The railway-coned tram wheels therefore run throughout the system on a more or less equal mixture of inclined and vertical rail, featuring two different running bands. They can hardly be expected to run sweetly throughout. Each wheel will have two equivalent running bands, one in the middle of the tread from railway running and one close to the flange from tramway running. Between the two running bands there will exist a very slight ridge which, I surmise, will “teeter” along the gauge-side edge of the centrally-located “railway” running band. At speed the conflicting ridges cause the wheel “not to know” which side of the ridge it ought to be on, constantly oscillating between one side of it and the other, knocking the flanges violently against the gauge faces of the rails. The oscillation problem persists, with no sign of any solution to it.
Metrolink’s original fleet of trams, the T68s, also hunted, but in a much less high-frequency way. They cyclically side-cut the rails on tangent (straight) track, yet rode well. The replacing M5000 trams, however, didn’t “agree with” the inherited T68 damage, and hunted violently at speed. Substantial, and premature, renewal of rails cured that problem. Some of the (now transposed) cyclically-sidecut rails can be seen re-installed in the track, for example close to Deansgate/Castlefield tram stop.
And so ends this rather protracted wander through a mire of affliction.
The kinematic envelope discussion was about tube trains, which is why I referred in my comment to “mind the gap”.
@MALCOLM 22 June 2019 at 11:33
“I believe that all DLR platforms are straight, thus “mind the gap” does not apply.”
There is a single station which gives a “Mind the Gap” message – in a counterpoint male voice – which is All Saints.
I’m not sure where the gap is, but it is announced.
DLR and curved platforms? None of them have the horrid curvature that you can see at Lewisham (mainline platform 1/2) or Bank (central line).
But that said, Mudchute platforms aren’t arrow straight, slight curvature at Island Gardens end.
I believe the key issue is not the curves in the running lines, which doubtless are OK, but the reverse curves in the DLR’s various crossovers of extremely short reverse radius, which will be an interesting place to stand in the “wide gangway”.
It’s notable that “modern” low-floor tramcars have a significant problem with curves such as at junctions or street corners, which need negotiating at snail’s pace. As such vehicles with multiple articulations are way longer than formerly, it all adds to running time well beyond what “old fashioned” trams managed. The Edinburgh Tram out to the airport is a classic, laid over open fields in a series of right-angle turns (presumably following the old field boundaries), which requires a string of dead slowings below walking pace out in open country.
Mr Beckton: You may be correct about modern trams going slowly in places, compared to old-fashioned trams. But as your Edinburgh example shows, any such slowness has little to do with the low floors, or indeeed anything about the tramcars themselves. It stems from design of routes with far more sharp curves than were traditionally used. Trams generally go as fast as is compatible with permitting standing passengers to remain upright (and the trams to remain on the rails), so we should blame the route designers rather than the tramcar designers for any excessive slowness.
@Malcolm – Indeed – the Viennese ULF sets, which have lowest floors anywhere, seem to cope with reverse curves without any signs of slowing to do so.
At a guess I would say that part of the reason for going slower around corners and through junctions is a greater desire to keep passengers upright and a desire to be kinder to those who are less mobile…
Modern low floor trams with body sections slung between bogie pods have a somewhat sharp lateral acceleration (lurch) when they enter curves. On conventional bogied vehicles, the rotation of the bogie and the other end of the car dampen the lateral acceleration This effect is particularly noticeable on the end pod which include the cabs which are cantilevered beyond the bogie. The cantilever magnifies the lurch, and so it might be that drivers compensate by slowing down a little. I must try and compare Stadler (pods and bodies) with Bombardier (conventional articulated) when I next go to Croydon.
If it is done for passenger safety issues (I always have attributed it to derailment prevention with the small flange profiles such lvehicles use) then it’s ironic that it coincides with making a far greater proportion of the passengers stand than older vehicles ever did, and also that there is concern for standees on curves but none for those in DLR vehicles which are hunting, as described by many above, and which in the front car on the downhill reverse-curved speedy descent westbound from the Connaught Bridge to Prince Regent station can give a passable impression of being inside a cocktail shaker.
@Mr. Beckton: “downhill reverse-curved speedy descent westbound from the Connaught Bridge to Prince Regent station can give a passable impression of being inside a cocktail shaker.”
I must visit that part of the DLR sometime, sounds like fun!
@Mr Beckton Stuttgart uses gangwayed sets on the U15, which is simultaneously tightly curved and steep.
Councillor Wood (represents Canary Wharf ward, Isle of Dogs) has published this reply from tfl to his FoI request for more detail on the recent DLR order.
Maybe I’ve not been paying enough attention but I’m rather surprised that the funds for additional trains (announced at least two years ago, Housing Infrastructure Fund) is still a matter of negotiation with the Treasury….
https://pbs.twimg.com/media/D-8yjkRUIAAv1nq.png