This year Tube Lines starts the installation of Seltrac transmission-based train control on London Underground's Jubilee Line. Roger Ford reports from the Highgate test centre on progress with the complex programme

THE KEY ELEMENTS of a new transmission-based train control system for London Underground's Jubilee and Northern lines are under evaluation on a 900m test track at Highgate depot. At three other locations on the Northern Line, inductive loops, axle-counters and point equipment are being tested in the working railway environment.

A comprehensive modernisation of LU's largely life-expired signalling equipment forms an integral part of the Public-Private Partnership concessions which began in 2003. Metronet Rail has decided to adopt the Westinghouse Distance-to-Go technology for five lines on its BCV and SSL networks (RG 8.03 p500), starting with the Victoria Line in 2012. The first route to be upgraded will be the Jubilee Line, and for this the JNP infrastructure concessionaire Tube Lines has selected Alcatel's Seltrac S40 transmission-based train control.

With detailed design of the Jubilee Line signalling upgrade nearing completion, Tube Lines has already started installation work, beginning at Stratford. This means commissioning of the first sections should start at the end of this year. Handover of the upgraded Jubilee Line is scheduled for December 31 2009. The combination of lengthened trains, plus the higher speeds and reduced headways possible with TBTC, will see a 21% capacity increase coupled with an 18% reduction in journey times.

Demonstrating the work in progress at Highgate at the end of last year, Tube Lines' Manager of Train System Delivery Dr Siv Bhamra said the signalling upgrade project was 'slightly ahead of programme and at or under budget'. Tube Lines is currently planning on the basis that installation will be completed in March 2009, nine months ahead of the contract schedule. 'We are going hell for leather to meet that date', emphasised Bhamra.

Tube Lines awarded a £300m contract for the resignalling work to Alcatel in October 2003. This covers 37route-km, 27 stations and 63 trains on the Jubilee Line, plus 58route-km, 50 stations and 106 trains on the Northern Line. The 7½-year deal also includes an option for the Piccadilly Line.

There is more to the upgrades than the installation of TBTC. Tube Lines is investing another £170m on 'engineering expertise and infrastructure changes', including new equipment rooms, track alterations, test facilities, project management and other enabling costs. A new control centre being built for the Northern Line will replace an existing facility in central London. When commissioned it will have the ability to act as back-up for the existing Jubilee Line control room at Neasden, and vice versa. The two lines' driver-training simulators are also being upgraded.

Within the main signalling contract, Alcatel Canada is responsible for detailed design of the Seltrac package. Installation, commissioning and testing of the lineside equipment has been subcontracted to Mouchel Parkman Metro.

Highgate's central role

Tube Lines has spent more than £1m setting up the Highgate test facility. It has taken over two tracks in the existing depot which have been segregated electrically from the rest of the site. Within its compound, the Tube Lines signalling team has its own safe method of working which has recorded no lost time incidents in 2·5 million h of work, a quarter of which covered the construction of the facility.

Several systems have been installed at Highgate for compatibility testing. One example is the control equipment for the Westinghouse platform screen doors used on the Jubilee Line between Westminster and North Greenwich. The inductive loops used to check train positioning and enable the doors on the correct side of each vehicle generate high levels of electromagnetic flux, which could interfere with the Seltrac antenna. On-site trials are also planned at Waterloo and Southwark stations.

While only 900m long, with two 400m loops plus four axle-counters, the Highgate track allows Tube Lines to run test trains in Automatic Train Operation mode at up to 50 km/h. Restricted manual operation can also be demonstrated. Stored test-run scenarios include stopping at a 'pseudo platform', including the correct-side door enabling function.

Commissioning of the Highgate facility started with debugging of the test train fitted with Seltrac onboard equipment, involving complex wiring modifications. Once the train was known to be functioning correctly, it was used to debug the track-mounted equipment. Then the associated command and management systems were commissioned.

The Highgate test track is being used for evaluation of both lineside and trainborne equipment, as well as the interfaces between the two. Specific tasks include test installation of the Seltrac inductive loops, testing the train's signal-to-noise ratios, axle-counter installation and the fitting of other equipment such as the onboard Vehicle Control Centre, the lineside control and supervision subsystem, the System Management Centre and the Station Controller Subsystem.

Complex acceptance process

Although Seltrac is already in service in the UK with the Docklands Light Railway, the system must go through London Underground's full safety acceptance procedure before use on the two metro lines. As a result, Tube Lines has adopted a deliberately conservative approach. The Infraco decided not to introduce the latest generation of Seltrac now available, but to specify the same technology as DLR, albeit the upgraded version used for Kowloon-Canton Railway Corp's WestRail line in Hong Kong.

This decision has already paid off. Initially it was thought that DLR would provide the basis for a simplified cross-acceptance process. In the event, the concept design submission was based on KCRC data leading to a 'Letter of No Objection' issued by HM Railway Inspectorate in May 2005. The Preliminary Design Review milestone was achieved on schedule in September last year.

UK acceptance procedures for signalling and safety equipment are notoriously difficult for manufacturers to negotiate. Before joining Tube Lines, Dr Bhamra had first-hand experience of the recent attempts to gain acceptance for standard European computer-based interlockings for use on Network Rail.

Highgate's test data supports the acceptance activity. Tube Lines is working to the UK-standard 'Yellow Book' process, which is based on two independent review procedures.

At each stage of the process Tube Lines' work is first endorsed by its own Independent Safety Assessor, the consultancy Aspect Assessment. Formal acceptance is then the responsibility of the System Review Panel, the membership of which is endorsed by LU and HMRI. Tube Lines has also added a third layer of supervision: regular peer reviews by a panel of experts, which meets every six months for a full day of presentations. These international experts provide support and guidance for the project team.

In addition to the acceptance process, the upgrade also has to meet the latest LU signalling standards, covering issues such as flank protection of conflicting moves, in addition to the specific requirements of TBTC. New operating rules have also had to be developed for normal and degraded operation as well as for the standard emergency mode.

Retrofitting the trains

With TBTC, the train forms an integral part of the signalling system. This means that 63 seven-car trainsets will have to be equipped for the Jubilee Line, followed by 106 for the Northern Line. Both fleets were built by Alstom to a similar design, and whilst they are relatively modern by LU standards, they were designed for different signalling and control philosophies which complicates the retrofitting of Seltrac equipment.

Both train designs include space for additional onboard signalling equipment - the aborted Westinghouse ATO in the case of the Jubilee Line stock and the route resignalling system being proposed for the Northern Line before the launch of the PPP. Using the latest version of Seltrac would have saved space, but the associated safety case proved to be more critical than the extra bulk of the earlier equipment. 'This version is affordable and gives the required performance', explained Bhamra.

Despite the inbuilt provision for modern signalling in both fleets, retrofitting inevitably introduces risk. Tube Lines therefore awarded a design subcontract to Alstom covering the installation of the Vehicle On Board Computer and the track-to-train communications antenna. The associated vehicle wiring design has been undertaken at Highgate, where the installation process is also being piloted.

Retrofitting of the Jubilee Line fleet was due to start in February, following completion of a programme to extend the trains from six to seven vehicles and add an extra four trainsets. At the outset, Bhamra had been concerned that fitting the on-train equipment might prove the hardest part of the project. However, over the past year, space has been found and design approval received, including compliance with fire regulations. 'I'm more confident now', he admitted in November.

Nevertheless, challenges remain, notably the fitting of Seltrac to the two lines' engineering train fleet, a little-reported part of the contract.

The contract provides for four trains to be out of service for Seltrac fitment at any time, two from each fleet. Cover for the Jubilee Line fleet is being provided by the four extra trains included in the seven-car programme. The Northern Line fleet had sufficient spare trains already.

Running line trials

In parallel with the development and acceptance work at Highgate, Tube Lines is trialling equipment in passive mode on the working railway. These 'advanced demonstrations' cover both piloting the equipment installation process and the subsequent monitoring of performance in a real-life operating environment.

Seltrac inductive loops have been installed at Bermondsey on the Jubilee Line and at Finchley Central on the Northern Line. The Bermondsey installation is on slab track, whereas at Finchley Central the Infraco is testing both the installation in a complex set of pointwork and the compatibility of the inductive loops with tamping machines used on ballasted surface track. Provision has to be made for the loops to be carried over the stretcher bars.

The loops provide the primary train location for Seltrac, backed up by axle-counters, which are being trialled at Willesden Green on the Jubilee Line. Once again, the trial axle-counter installation is being used to monitor the performance of the equipment in a live environment.

Central to the success of the upgrade will be the smooth cut-over to Seltrac from the existing signalling. Tube Lines has a contract with Westinghouse Rail Systems and Metronet to support the migration, with Westinghouse having staff and signalling cubicles at Highgate.

One of the benefits of TBTC is that it can be installed as an overlay on the existing signalling. Dual-fitted trains will be able to start driver training on the northern end of the Jubilee Line between Kingsbury and Canons Park in October, and also on four dedicated sections at the Stratford end of the line.

Once sufficient trains have been equipped with Seltrac, Tube Lines will be able to switch off the existing signalling and conduct full TBTC trials during engineering hours. These will form a key part of the final acceptance phase, after which live railway operations will be switched over in a single move.

Unlike Metronet's plans for the Victoria Line, where resignalling has to be dovetailed with replacement of the rolling stock fleet, there are no plans to operate a mixed conventional and TBTC service on the Jubilee Line.

As the wayside installation work on the Jubilee Line is completed, the teams responsible will roll forward to start work on the Northern Line at the end of this year. This is a much larger and more complex network of interconnecting routes, but thanks to the experience gained on the Jubilee Line, Tube Lines expects to complete the Northern Line two years later, in January 2012.

  • CAPTION: Among the equipment undergoing proving trials at Tube Lines' Highgate test track are an axle-counter (left) and Seltrac trackside equipment module (right)
  • CAPTION: Clearly visible on the Highgate test track are the inductive loop cables used for primary train location, and the counter heads for the back-up axle-counter installation

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A la suite de la création d'une voie d'essais à Highgate et aux tests de composants essentiels à divers endroits de la Northern Line du London Underground, le concessionnaire de l'infrastructure Tube Lines a commencé les travaux plus t?€?t cette année pour installer le Seltrac S40, équipement de contr?€?le des trains par transmission, sur la Jubilee Line. Roger Ford a visité Highgate pour jeter un coup d'oeil aux progrès réalisés par le projet de 470 millions de livres, qui équipera entièrement la Jubilee Line en 2009 et auquel la Northern Line sera convertie en 2011

Jubilee und Northern Lines führen Sicherungstechnik-Erneuerung bei dem Londoner U-Bahn an

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Tras la creación de una vía de pruebas en Highgate y las pruebas de componentes clave realizadas in-situ en la línea Northern del metro londinense, el concesionario de infraestructuras Tube Lines comenzó a trabajar a principios de este año para la instalación del sistema Seltrac S40 con transmisión de datos vía-tren en la línea Jubilee del metro. Roger Ford visitó Highgate para observar el progreso del proyecto de 470 millones de libras esterlinas mediante el cual se completar? la instalación en la línea Jubilee en 2009 y la conversión de la línea Northern para 2011

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