London: 15-minute reboots hold up Dome line : LUSENET : Grassroots Information Coordination Center (GICC) : One Thread

15-minute reboots hold up Dome line
Mike Simons

Failing IT systems lie behind the signalling problems that have dogged the launch of London Underground's Jubilee Line extension.

Transport minister Keith Hill told MPs who had complained about problems on the Jubilee Line project that "the challenges were expected" and the situation is improving.

However, London Underground is struggling to overcome problems with ambitious new signalling technology, which has had to be abandoned and replaced with tried and trusted systems. It has also felt the impact of short cuts taken to get the line running in time for the new year celebrations at the Millennium Dome.

Train drivers on London's Jubilee Line extension are considering industrial action over signalling problems, as London Underground battles to make its system reliable.

The Jubilee Line extension was designed to run with computerised "moving block" signalling, which did away with the need for trackside signals. This was abandoned in 1997 for traditional signaling. However, this created new problems when interfacing with other systems.

London Underground told Computer Weekly that it is engaged in a "programme of enhancements to the signalling system, which will make the system more immune to equipment failures".

The company also said it is improving fault recording and alarm management to "provide more specific information for technicians in the event of equipment failure".

Hill told MPs that signal-related failures and delays were caused "while the control computer has to be rebooted," which, "typically takes 10 to 15 minutes".

He also admitted to faults and operating procedure problems with platform-edge doors, which have been introduced at some stations.

Software upgrades and changes to improve the reliability of the signalling system are scheduled to be completed by the end of June. However, the problem could continue - with signalling work scheduled to take place along the whole of the Jubilee Line all year.

JLE problems

Poorly sited signals
Software problems with platform edge doors
Over sensitive signalling system that shuts down unnecessarily
Constant software upgrades and changes to account for timetable and technical changes


Signalling contractor Westinghouse planned to use the moving block system, which dispensed with trackside signalling and used computer control and radio signals to maintain safe distances between trains. It was abandoned in 1997 after persistent failure to make the system work. It was replaced by a traditional fixed-block system, which allows one train into a section of track at a time.

-- Jim McAteer (, April 28, 2000


Correct link: rchive/news/20000427/cwcontainer.asp?name=C7.HTML&SubSection=1

-- Jim McAteer (, April 28, 2000.

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