Very logically, and very conveniently for us, TfL’s Finance and Policy panel has now published details of the proposed infrastructure upgrade to the Jubilee and Northern lines. So as a nice follow up to our look at the future train procurement for these lines, we are now able to report on what is proposed in terms of upgrades to support them.

The great unknown… until now

It has been a source of frustration for us over the years that despite knowing that there was an upgrade plan for the Jubilee and Northern lines – in contrast to the others – we really did not know the details. This was especially true for the Northern line although in part the reason for this was fairly clear – despite knowing the basics of what was required, TfL hadn’t decided the real details themselves. The options for the Northern line, in particular, have been re-evaluated many times it is only recently that a final decision appears to have been made.

Thoroughbred stock

At the heart of the matter lies a problem that London Underground have always tried very hard to avoid – running mixed stock on a single line. London Underground have long preferred to run similarly performing (and similarly looking) trains on a particular line because mixed stock operation has a whole host of implications – increased complexity of driver training, delayed boarding as people adjust their position on the platform due to variable door position, extra training for fitters and extra spares needing to be kept, just to name a few. There is also a small potential safety issue with the risk of drivers becoming confused by being in charge of different types of train although this risk should be less critical these days with Automatic Train Operation (ATO).

As well as day to day issues, operating mixed stock can be problematic if, in order to do so, you need to purchase new trains for the fleet. If this is the case then buying stock midway through its expected life is almost the worst of all options. In an ideal world it is much more preferable to buy it earlier, losing just a just a few years of use when the stock is starting to become less reliable anyway, or leave it another ten years and think of it as an advance delivery of the full new fleet.

Needs must

Of course if the Underground was operating with only slow growth one could simply put off the fateful day when more trains were introduced. The trouble is that passenger numbers are rising rapidly and all of the ways to deal with that here require new trains. Leaving it until replacement stock is due naturally is thus not really practical. Interestingly, at the Rail and Underground panel, replacement of the Northern line fleet was talked about “for the late 2030s” and the latest briefing for the Northern line upgrade states:

The current assumption is that the JNAT [Jubilee and Northern Additional Trains] trains would be withdrawn in 2040 at the same time as the existing Northern line 95 Tube Stock fleet and the business case would erode if the number of years of beneficial use were reduced.

So the plan already appears to be to expect the existing Northern (and presumably Jubilee) trains to last around 45 years in service. Such an assumption is not at all unreasonable based on the age of much of the stock recently withdrawn, and the generally better construction of modern trains. The 1972 stock is mostly regarded as being the last of the ‘old’ generation and the 1973 stock being the first of the new, but with the attendant problems of being first in an age when metro trains were undergoing a radical design change. As has been commented on before, it is looking more and more likely that by the time trains for the first four lines of New Tube for London are fully introduced it will almost be time to replace trains on all or part of the Northern line.

As soon as possible – but no sooner

It is clear that, once you have decided to buy the trains midway through the greater part of the fleet’s lifecycle, it makes sense to introduce the trains as soon as possible to get the maximum life possible out of them. The difficulty is that an awful lot of preparation work needs to be done before additional trains can be brought into service.

The case for the work on the Jubilee line

The case for the Jubilee line is relatively simple and, we are told in the Jubilee line briefing document, compelling. The line is very much at capacity now, with a wait for a second or third train in the peaks quite commonplace at various locations due to the inability of the passenger to board the first train that arrives. Part of the reason for this is undoubtedly the work at London Bridge main line station, but the trains will almost certainly fill up again to crush loading within weeks of this work being completed.

The argument then goes that, with the signalling upgrade complete, and demand still greatly outstripping supply, it makes sense to buy extra trains to add extra capacity to an infrastructure that is mostly already in place to take them. The trouble is that the bits that aren’t there yet on the Jubilee line are still expensive and would cost around £100 million to provide. The 10 additional trains are expected to cost around another £150 million for a life of approximately 20 years. Very approximately, the initial capital cost for a seven car train works out at around £100,000 per carriage per year – or £300 per carriage, per day of its expected life. At least with the capital infrastructure works you only have to do it once and it is done, more or less, forever.

Although the sums involved for extra stock may appear huge, one could quite reasonably expect that, even when other cost such as drivers and maintenance are taken into account, the trains would generate more revenue over this period than they would cost. While the report does not go quite as far as saying as much it does state:

No revenue abstraction from other TfL modes is assumed as the assessment identified that the additional capacity provided will be utilised by currently deterred demand, rather than diversion from other options.

Without detailed data it is impossible to be sure, but one suspects that the new trains may well pay their own way simply by increasing income due to increased fare revenue. If that were the situation then the case for purchase is almost compelling for that reason alone. The main concern, of course, would be a future mayoral policy on fares that would mean that revenue created would not be as high as expected.

The work involved on the Jubilee line

Very conveniently the work involved is listed as:

  • power strengthening works at six substations by June 2018
  • four cooling ventilation fan upgrades by June 2018
  • conversion of a cleaning road at Stratford Market Depot into a general maintenance road by March 2017 and provision of two roads at Neasden depot for maintenance of Jubilee Line trains by August 2017
  • conversion of Temporary Fit Out Shed at Stratford Market Depot into three stabling roads by July 2020
  • renewal and upgrade of the crossover at West Hampstead by March 2017
  • five signalling workstreams by October 2019
  • necessary modifications to the existing fleet of 96TS for operational consistency
  • all associated maintenance and operating changes

Getting the optimum number of trains

The report has a short, but sufficient, explanation of why they proposed a ten train upgrade. It seems that this number was necessary to get the desired 36tph through the central West Hampstead – North Greenwich section. More trains ordered would not lead to more frequent trains operated in the central area, but would improve the service out towards Stanmore. There would possibly be a case for this but it would involve an extra eight trains, which would presumably cost around £120m, and an additional stabling scheme at Stanmore, which would presumably have costed around £50m to bring the total extra to the quoted £170 million – a figure which it was felt could not be justified. As always, the critical thing is capacity and, whilst improving the service further out would bring customer benefits and time saving, it would not do anything for increasing capacity where it is needed.

The complexities of terminating Jubilee trains in the West

Jublilee line principal reversing locations

Diagram showing principal Jubilee line terminating locations

The Jubilee has a very discernible pattern at the eastern end of the line for terminating trains. This is that three trains in four terminate at Stratford and the fourth terminates at North Greenwich. At the other end there is no such regularity. Around 19 terminate at Stanmore in the peak hour, five at Wembley Park and six at Willesden Green. It is possible to terminate trains at West Hampstead but this is not currently favoured.

West Hampstead is the key

The plan for increasing the service on the Jubilee line to 36tph with so few additional trains relies on using that terminating facility at West Hampstead. A round trip from West Hampstead to Stratford would be slightly in excess of 80mins suggesting nine trains would be necessary to provide an additional 6tph. Allow one extra for maintenance and you have the ten train requirement. Of course, it is not quite as simple as that because the service pattern will change slightly for the existing trains and, as we have already remarked, not all trains at the eastern end of the line terminate at Stratford. The believed intention is for trains westbound to be in a Stanmore, Willesden Green, Stanmore, West Hampstead sequence. This would give Stanmore an almost identical service to that of today but further south of West Hampstead it would be better.

One stop closer to central London from West Hampstead is Finchley Road where there is considerable interchange from the Metropolitan line to the Jubilee line in the morning peak. Finchley Road is probably the first station southwards from Stanmore that really merits a 36tph service if possible.

Early gains

The plan is for authority to be given to proceed in the very near future so that works to upgrade West Hampstead crossover – presumably with faster turnout speed – can be done in order to take advantage of two planned closures early in 2017. This would then be available for reversing in May 2017 and it should be possible with the existing stock to introduce 32tph by April 2018 – just over two years away.

Any indication of what service can run from April 2018 is naturally speculative, but the smart money at LR Towers is on London Underground running the line to the future intended pattern as this would enable the revised service pattern to settle down. If there was any shortfall of trains this could be taken into account by terminating one or two Stanmore trains short at Wembley Park. Assuming terminating at Wembley Park was not necessary, this would mean that in the peak there would be 16tph to Stanmore, 24tph to Willesden Green and 32tph to West Hampstead. At the other end Stratford would have 24tph rather than 22½tph and 8tph rather than 7½tph would terminate at North Greenwich.

Full service by April 2020

If the experience on the Victoria line is anything to go by, London Underground will be cautious as it increases service from 32tph to 36tph. Quite how they will increment the service remains to be seen and will probably depend on when they decide that the working timetable must take into account time periods shorter than a quarter of a minute. Realistically, 34tph (a train every 105 seconds) is as frequently as one can go based on a working timetable with quarter minute increments.

It is worth noting that, on completion of this project, it is hard to see how one could improve the Jubilee line service for the next twenty years beyond. By then thoughts will turn to replacing at least the rolling stock, maybe the signalling and possibly the platform edge doors to take into account any different door spacing on future stock.

It is believed that the 2022 off-peak Jubilee line service will be 27tph between West Hampstead and North Greenwich – the same off-peak frequency as currently operates on the Victoria line.

Northern line changes not so advanced…

In contrast to the Jubilee line Upgrade 2, where the additional authority requested for the next phase is around £77 million, the Northern line briefing document requests only a modest £8m for Northern line Upgrade 2. The reason for the much lesser sum is because, unlike the Jubilee line, all that is being asked for is money to deliver concept designs prior to the work being carried out. This shows that work on the Northern line upgrade is not in as nearly advanced stage as the Jubilee line. This could explain why previous publicised proposals to bring the upgrade forward to 2020 were simply not going to happen – there was too much work still to do.

The true cost of upgrading the Northern line is likely to be much higher – an estimated £700m with the trains themselves seemingly only a third of that cost. This is a stark reminder that replacing trains like for like is relatively cheap. Additional capacity generally can cause considerable extra one-time costs as sidings, power upgrades, administration offices and extra depots to service the trains may be required. Often there will be the extra train that causes a new set of costs to be required (such as the train that is one more than there is space for in the depot, so that means a new depot) and the aim generally is to provide the overall package that provides best value for money.

…But more involved

It is clear that the work involved on the Northern line has considerably more scope than that on the Jubilee line despite both intending to increase the number of trains by 6tph. A lot of this is down to the Jubilee line being more modern and, perhaps, because it was originally planned to run 36tph on the Jubilee line – or at least signal it for 36tph, which isn’t quite the same thing. It does appear that there is a lot of work involved on the Northern line that simply would not be needed on the Jubilee line.

Again, conveniently, a list is supplied of the works required. It is much more extensive than that for the Jubilee line and part of this appears to be because of accommodation necessary at two station-based driver sign-on locations – Battersea Power Station and East Finchley. Whereas the one at Battersea Power Station obviously will be an entirely new location, the accommodation for the one at East Finchley will be a replacement for the existing facilities suggesting an expected increase in the number of drivers to be based there.

Fairly obviously, because there are many more kilometres of track, the upgrade to the power supply is more involved. This even includes installation of low loss conductor composite rail, which you would have thought would have already been done and could be justified on its own merits.

The list of specific upgrades necessary is described differently from the Jubilee line list and refers to “[t]he scope of the preferred 30tph option”. Read into that what you will.

The list is as follows:

  • 17 additional trains (procured via the Jubilee and Northern Line Additional Trains Project (JNAT))
  • additional stabling at Morden and Highgate
  • provision of a new heavy maintenance depot at Highgate
  • installation of a new scissors crossover for reversing at East Finchley
  • provision of Train Crew Accommodation at East Finchley and fitting out at Battersea
  • reconfiguration of Morden depot
  • five signalling workstreams:
    (i) out-stabling (to reduce the number of additional stabling berths required)
    (ii) signalling pinchpoint improvements (to support throughput)
    (iii) coasting (for energy efficiency)
    (iv) depot signalling at Highgate and Morden
    (v) modification to support new track layouts
  • power upgrades (22 substation upgrades, new feeder cable at 14 sites, increased regenerative braking)
  • low loss composite conductor Rail, fan renewal and two cooling schemes
  • upgrades to track including development of new track layouts for service pattern and stabling
  • all associated maintenance and operating changes

It is clear that it is quite a challenge to find somewhere to stable the 17 trains.

One of the things that is surprising is the requirement to put a coasting function into the ATO software. This is to reduce the heat generated by the trains during the off-peak period, but it is slightly strange that this is specifically mentioned as required for the Northern line but not for the Jubilee. It is no insult to say that Thales are probably quite pleased that luck has presented them with an opportunity to create something for London Underground (and to bill for doing so) which will make their system more attractive for future sales.

The East Finchley scissors crossover mystery

East Finchley

Diagrammatic current track layout at East Finchley

Normally these briefing papers are fairly clear but one thing that is far from obvious is exactly how a scissors crossover at Each Finchley could assist with reversing. The layout at East Finchley is highly unusual for historical reasons and the inner two platforms (2 & 3) only serve Highgate sidings. The location of tunnel mouths means that it is not clear at all where a scissor crossover could be located that would enable trains to reverse.

Just to add to the mystery, one wonders why East Finchley would be considered at all given that Finchley Central, one stop further down the line, has a much more flexible arrangement that gives a number of reversing options. Possible reasons for choosing East Finchley are that to terminate at Finchley Central requires more rolling stock and a desire to terminate trains at a signing on location.

Finchley Central

Diagrammatic current track layout at Finchley Central

It would be interesting to know the reason why the scissors crossover is required. The most likely explanation is that it is because High Barnet and Mill Hill East on their own cannot handle all of the planned 30tph peak period terminating trains. With Mill Hill East only about to handle just over 5tph and High Barnet currently handling 18-19tph one would imagine the plan to be something like terminating 5tph at East Finchley, leaving 20tph to High Barnet with a slightly awkward pattern between East Finchley and High Barnet.

An alternative explanation could just be that it is recognised that the off-peak service north of East Finchley is unduly frequent – it is currently 20tph – and that it could be reduced without a significant adverse impact on customers. An off-peak service of a train every 5 minutes (12tph) would not seem to be excessively frugal in zones 4 and 5. Of course the peak and off-peak reasoning need not be mutually exclusive and it could be a combination of the two requirements.

More or less?

Because the work on the Northern line Upgrade 2 is not so advanced there is not a total commitment to 30tph, but it is felt that if this figure could not be achieved and a lesser frequency committed to then the money spent on this lesser increase would be disproportionally high. This would largely be due to infrastructure works, which would be necessary regardless of the level of improved service provided.

In the paper to the Finance & Planning panel there is no suggestion that the work should not or may not go ahead – although it is not so emphatic as the Jubilee line recommendation that it should go ahead. It does say it should not be deferred because the costs remain the same but the benefit is reduced and it does add that:

If NLU2 were delayed, then it may be a better strategy to abort this project and consider other strategic options for delivering additional capacity.

So, in essence, do it now or don’t do it at all.

If the Northern line upgrade goes ahead then a decision on the main project needs to be made by June 2017, with the aim of providing 30tph by 2022. As with the Jubilee line, it is hard to see how, subsequent to that, services can be improved in any cost effective way until replacement of rolling stock around 2040. If the project does not go ahead then the Northern line would have been the only line to have an improvement plan rejected and one would wonder how long before it regains its old epithet of the Misery line. Either way one would be stretching a point to call the currently proposed Northern line improvement (30tph) “world class capacity” though the term would be deserved for the Jubilee line improvement (34-36tph). This would rightfully place the Jubilee alongside the Victoria in achieving a level of service that could legitimately be regarded as one of the best in the world.

Want to discuss this article in person? Then why not join us on March 10th in Soho for the LR Monthly Meetup.

Written by Pedantic of Purley