The Status of the Jubilee Line Upgrades

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Yesterday saw a Special Board Meeting at TfL. The key item on the agenda was a report on the current status of the Jubilee Line Upgrades. The papers for this can now be found online and they make for some pretty damning reading.

The report were intended to broach three topics:

1) What stage the Jubilee Upgrades are currently at
2) How the new signalling will be commissioned
3) Any risks that currently exist due to the above

Where are we now?

The report largely focusses on the new Transmission Based Train Control (TBTC) system Thales have been tasked with putting in place, as this is the key component of the contract.

The report begins by illustrating once again the changes that have taken place to the migration strategy over the last few years (which we have previously covered in more detail here). Essentially, the initial plan was to commission the new signalling system in four blocks, with trains switching from old to new control methods (and back again) at one of three system boundaries. This would have allowed the upgrades to be phased in gradually with the minimum risk and disruption should any problems occur.


As the timetable slipped, however, Tube Lines modified this strategy. In an effort to remain on time and schedule, they removed the system boundaries between J2 and 3 in May 2008 and then the boundary between J23 and 4 in November 2009. This meant they moved to a strategy whereby larger and larger blocks would need to be commissioned simultaneously. The net result of this has been that the only system boundary that now remains is the last – at Dollis Hill.

Trials and Tribulations

During the 2009 Christmas closure, Tube Lines ran the first real system-proving trial on the J23 section of the line. This was followed, at Easter, by an attempt to cut over the entire J234 section, including Stratford Market Depot (the Depot tests having already been thought successfully completed). The Easter tests were (to put it mildly) not promising, with bugs and reliability issues surfacing as well as train and system reliability issues – a total of 22 delay minutes had been forecast for this closure, in reality 463 occured . Further tests during the May Bank Holiday resulted in more bugs and problems emerging (785 delay minutes this time against the forecast of 240).

This situation apparently remains true to date – J234 is currently uncommissionable, as the report starkly makes clear:

Since then further trial operations have been undertaken and the system has still proved to be unreliable with approximately 750 to 1000 delay minutes per weekend which is many times worse than the current levels of service on the line. Hence the decision has been taken not to put the service into revenue service until the reliability issues have been addressed and further software fixes implemented.

even were it to be ready to be brought online, there remains a serious gap in Train Operators trained in the new system’s use – as the report points out:

It is not possible to train drivers on a system that is not working

The situation in J5 is apparently even less promising. This is arguably the most complex area on the system, including, as it does, a mixed mode area where the Jubilee and Metropolitan line overlap and the complex interface with Neasden Depot. Here testing is only really just commencing and there is also already a backlog of known bugs and defects that need to be fixed.

“The Jubilee Line Will Be Closed This Weekend…”

The Report continues by looking at the approach taken for testing and management of the TBTC system, and questioning whether the approach taken was the correct one. It begins with a theme that will be familiar to those who had followed the war of words that took place between Tube Lines and TfL over the course of the last twelve months – comparing the approach Tube Lines took to the Jubilee Upgrades to that taken on the Madrid Metro and the Victoria Line.

Minimising closures – particularly at weekends – the report implies, should be a requirement of a system such as this, and that can be achieved through a number of techniques.

Passive testing, whereby equipment is installed but isolated from vital functions so that it can be tested in traffic hours, is one option. Similarly, extensive offsite simulation (wherever possible on a test track that mirrors the live environment as accurately as possible) can help minimise the need for (and the issues of) live testing.

The report highlights that neither of the above techniques took place on the Jubilee Line (although there is limited facility for testing at the Highgate Test Facility) – a major contributor to both the risk that remains and the problems that have occured during the live testing so far (such as at Christmas and Easter).

Additionally the report highlights that Tube Lines opted not to implement an overlay mode in the TBTC system. An overlay mode allows the new system to effectively sit “on top” of the old one – when the new system isn’t being tested, the old system can be read through the overlay. The advantage of this approach is that it means testing can take place without a lengthy switchover period and is the approach that has been taken on the Victoria Line.

Incredibly, the report reveals, the lack of an overlay mode means that currently the process of “over and backing” takes at least ten hours on the Jubilee Line – effectively meaning that an entire day of closures is required to allow one hour of testing.

Trains and Depots

The report provides additional details of where things stand with regards to trains and depots. Currently, only 20 trains (of the 63 total trains on the line) are sufficiently tested and reliable on the new system to be used for passenger service. This is only just about sufficient for running a J23 service (which requires 10tph) and obviously leaves no capacity for unit failures. The reasons for this low number are apparently twofold – firstly, the lack of a robust testing facility has meant that the only real way to identify “unhealthy” trains is to run them in the live environment (which in itself is obviously not ideal), and secondly that the very lack of such a working live environment until recently has meant that testing simply couldn’t take place.

A New (Or Rather an Old) Proposal for Commissioning.

The report confirms that TLL’s current proposal is that which they suggested several months back (linked to above). This is that the commissioning process return to a phased approach – bringing sections on line indendently where possible.

Unfortunately, due to the fact that there are now no system boundaries in place apart from at Dollis Hill, this can only be achieved by splitting the line in two – effectively turning the Jubilee Line into two seperate lines at weekends by imposing a “hard” boundary between services (as trains will be unable to move from one signalling method to the other).

In full, Tube Lines current proposal is as follows:

Phase 1

Initially TLL would introduce TBTC mode east of Waterloo, while a ‘normal’ service operates north from Green Park; this would mean a reduced frequency service on the eastern half, through Canary Wharf and North Greenwich (up to 10 trains per hour compared with the usual 18) at weekends, and no through service from north to south, disrupting longer journeys, but it would reduce the number of full weekend closures.

Phase 2

Once the J23 section is at an acceptable level of reliability, J4 would be added and TLL would ‘swap over’, with the section from Green Park to Stanmore then operating in TBTC signalling mode and the Waterloo to Stratford section under conventional signalling in tripcock mode. Once its reliability is proven J234 will be brought into full revenue service on weekdays as well as weekends. During this phase J5 would continue to operate under conventional signalling in tripcock mode.

Phase 3

Finally, once the J5 section has proven to be at an acceptable reliability level, the whole line can be commissioned in TBTC mode in full passenger service for the full weekday service, and the upgrade completed.

Serco’s Report

In addition to the above, London Underground asked Serco to carry out an indpendent assessment of the current state of affairs. The board report also includes this in full. It confirms much of the above and adds the interface with the Bakerloo Line at Baker Street to the lengthy list of areas in which the system is currently incomplete. It also includes several other key points that are worth highlighting.

With regards to the Jubilee Line, it concludes that not only was commissioning best-practice not followed, but that it is not yet possible to establish a date at which the Upgrades can be completed (London Underground’s estimate in their section of the report was October 2010 at the very, very, earliest). They indicated that even after J234 enter passenger service, the upgrades in J5 will likely take a further six months. Physically, the Serco report concludes, the system is now in place, but the testing and commissioning is currently nowhere near the level it needs to be at for revenue operation.

The Northern Line

Finally, Serco’s report also looks briefly at progress on the Northern Line upgrades, and here it is even more damning (and deserves to be quoted in full). London Underground have already publicly confirmed that these will not be completed by the Olympics, but Serco’s report effectively suggests that it will not be until 2014 that they will fully manifest:

Serco was asked to review the Northern Line upgrade programme as recently published by TLL. The review of this programme shows significant slippage with it being forecast that the upgrade will not be complete until May 2012, some five months after the latest implementation date. Furthermore the programme appears to be both embryonic with dates continuing to slip and to be based on the JLU approach with a high dependency on closures. Furthermore a number of intermediate completion dates look very optimistic. With the majority of this programme still yet to run, it is difficult to provide an accurate forecast of likely completion date. However, the slippage experienced to date suggests that if this programme were to proceed then it is likely that the upgrade would not be complete until late 2013. This date is conditional to a large extent on the degree of access provided, and the amount of resource drawn off the project to complete and deal with problems that arise on the Jubilee Line. As a consequence it is felt that even this estimate may be optimistic.

Overall, the report makes stark reading. Whatever the outcome of the current work to decide a way forward on the Jubilee Line is, a few things seem clear – it will be a long time and there will be much more disruption before we see the Jubilee Line fully upgraded. Worse, what reprocutions this has had (and has yet to have) for the Northern Line Upgrade is still worryingly unclear.

Written by John Bull