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Tube bosses fire warning shot over 'unacceptable' signalling problems

Tube bosses have warned the supply chain that it will no longer stand for “unacceptable” teething problems as seen on the Jubilee Line upgrade in future projects.

London Underground managing director Mike Brown has told the industry that he does not want to see the same kind of dips in performance when new signalling is introduced on the Northern and sub-surface lines in the next four to seven years.

His comments to NCE’s London Rail conference last week came as contractors finally commissioned a form of moving block signalling on the Jubilee Line, more than two years later than planned.

In doing so, commuters have faced routine weekend line closures and frequent breakdowns and line suspensions, much to the fury of London mayor Boris Johnson.

Transmission Based Train Control (TBTC) using Thales’s SelTrac S40 system was operated across the whole line for the first time on Monday 27 June ahead of introducing a revised timetable later this month.

Thales’s system is also set to be installed on the Northern Line upgrade that will begin later this year and complete in 2014. Bombardier will install its Cityflo 650 Automatic Train Control (ATC) system on the sub-surface lines in work that will complete in 2018.

Brown said he has told them that he expects to see none of the problems that have beset the Jubilee Line upgrade.

“There will be no more learning curve; no more bathtub dips in [line] performance after the new technology is installed,” he said. “No-one would accept an airliner with a one in three chance of falling out of an air, and neither should we [accept a similar level performance from our technology].

“That’s what I tell the supply chain when I see them,” he said.

When complete, the Northern Line upgrade will deliver faster, more frequent and more reliable train services, increasing capacity by 20% and cutting journey times by around 18%.

London Underground inherited the Jubilee Line upgrade works from PPP contractor Tube Lines, and said lessons have been learned ahead of the Northern Line upgrade.

A new approach is being taken on the Northern Line that will mean significantly fewer weekend closures than originally planned by Tube Lines, with no early evening closures.

Under the PPP, Tube Lines had proposed 65 weekend closures on the Northern Line, many of which would have closed the whole line, or large parts of it. Instead, there will now be just eight full line weekend closures for the installation and testing of the new signalling system.

London Underground will do this by installing the new signalling using an overlay system, which allows passenger trains to still use the old system while the new is being installed and tested, but also allows test trains to run without reconfiguring the system.

On the Jubilee Line testing could only be carried out after reconfiguring the system, a process which could take up to 10 hours. As a result effective testing could only be carried out in weekend closures.

The Jubilee Line upgrade also suffered from difficulties making the TBTC system work with manual systems at depots at Neasdon and Stratford.

Completion of the Jubilee Line upgrade marks the end of an 11 year wait for moving block signalling to be installed on the line.

Thales, then Alcatel, was brought in in October 2003 to install a simplified moving block system on the line by 2009, 10 years after plans to introduce a similar system were scrapped.

Moving block signalling was originally commissioned from supplier Westinghouse for the Jubilee Line Extension, which opened in 1999.

The previously untried Westinghouse system was to enable the frequency of trains to be increased by allowing trains to travel closer together, and was to have increasing line capacity by 50%. It was to be flexible enough to allow changes to distances between trains depending on their speed.

But the system was abandoned after problems with the inter-train communications system and with communications between trains and the train control centre (NCE 21 May 1998).

There were also problems marrying the Westinghouse system with the existing fixed block system on the rest of the Jubilee Line.

The new signalling system now installed by Thales was described by Tube Lines as a “halfway house” between moving block and traditional signalling.

It uses inter-train communications technology to reduce headways, but keeps fixed minimum distances between them. Full moving block signalling allows the gap to close as trains slow down.

It will increase line capacity by 33%.

Thales’s 2003 contract also covered installing the system on the Northern Line by 2011. This work has now been delayed by three years because of the Jubilee Line delays.

Bombardier’s system that is to be installed on the Circle, District, Hammersmith & City and Metropolitan lines is a full moving block system as used on 13 lines around the world, including the Madrid Metro.

Its £354M deal will see 310km of track and 191 passenger trains equipped with the new signalling system without the need for any full weekend closures.

The upgrade will deliver 24% more capacity on the District line, 27% more capacity on the Metropolitan Line and a massive 65% more capacity on the Circle and Hammersmith & City lines.

In total the upgrade will provide space for an extra 17,500 more passengers each hour –increasing the capacity from 26,000 to 43,500 passengers an hour.

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