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.