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Resignalling the Victoria Line

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Much has been written about the excellent way in which public transport performed during the 2012 London Olympic Games. This was due to detailed planning and to making sure that major improvement projects by both London Underground and Network Rail were completed in advance of the competitors and spectators arriving.

The Rail Engineer has looked at several of those projects. One that it has not was the commissioning by Invensys Rail of the seventh and final asset replacement stage of the Victoria Line Upgrade (VLU) Project, marking the completion of a challenging nine year programme.

Invensys delivered the upgrade in partnership with London Underground (LU) and Bombardier Transportation, the programme seeing the replacement of all the Victoria Line’s rolling stock and signalling and ultimately providing improved headways and journey times. The upgrade programme has delivered a ‘30 trains per hour’ service, providing passengers with faster, more reliable and more comfortable journeys, with week day peak services increasing from 28 to 30 trains per hour and off peak services from 23 to 24 trains per hour.

Overlaying the new system

A little over 13 miles long, the Victoria Line was originally opened in four sections between 1968 and 1972. The line is predominantly formed of a deep level tube tunnel which serves 16 stations with a fleet of 43 trains (37 of which are in service at peak hours).

The design and installation teams for the VLU programme therefore faced a number of significant challenges, the project representing a first for LU in that it required migration from one Automatic Train Operation (ATO) system to another, with Invensys Rail’s Distance to Go-Radio (DTG-R) trackside equipment being overlaid on to the legacy signalling system, transmitting both the new radio messages and legacy track circuit codes during the migration period for the new rolling stock fleets.

Train detection, interlocking and point detection and control continued to be delivered by the legacy signalling system, which also switched and transmitted the legacy Automatic Train Control (ATC) track circuit codes to the 1967 stock trains. Invensys delivered new ATO and Automatic Train Protection (ATP) solutions which were overlaid onto the existing infrastructure and which enabled mixed operation of the original 1967 fleet and new rolling stock. The overlay solution allowed the first of the 47 new Bombardier 09TS trains to start running on the live passenger-carrying railway three years ahead of the final project completion, minimising service disruption throughout the project.

The ATP system provides train protection for over-speed; driving limit enforcement (end of authority) and protection limit enforcement (limit of movement authority), while the ATO

provides automatic driving functionality for control within driving limits, speed and distance; signal stopping and auto-restarting; platform stopping (to within +/- 1 metre of the actual stopping mark) as well as the potential for automatic door opening.

The new 09TS fleet began to enter service in January 2010 and has already accumulated over 10.2 million kilometres of passenger operation. As part of the migration stage, the new Signalling Centre at Osbourne House also took control of the legacy interlockings and the legacy control room, with the control centre commencing continuous operations in January 2011.

Removing the legacy

An asset replacement programme was undertaken by Invensys after the last of the 1967 stock was withdrawn. Over 15 months and seven stage commissionings, the company successfully removed the last of the legacy signalling equipment and installed new WESTLED signals, FS2550 track circuits and a full range of platform equipment. The company’s WESTRACE solution now controls the entire line which is split into 16 interlockings, linked to the signalling control system.

The final stage was delivered over a 27-hour weekend closure in July and saw the commissioning of bi-directional signalling between Seven Sisters and Northumberland Park Depot. New control centre operations were also installed, together with an upgraded version of DTG-R train data, which provides full functionality for control of the entire Victoria Line.

“Migration to the new signalling system presented many challenges, both technical and operational. Keeping the railway running whilst the signalling system was being replaced required a realistic and realisable migration plan, while recognising the constraints on access to the railway. Throughout the project, the Victoria Line remained operational during the day. Access was generally limited to three extended nights per week, plus a number of weekend shutdowns, limiting disruption to passengers and ensuring a smooth transition from the legacy to the new system”, said Invensys Rail’s delivery director, Matt Kent.

“This has been one of the longest, most complex and most challenging projects we have undertaken, but the result is a railway which is delivering significantly improved capacity, performance and reliability for London Underground and its passengers, as well as a greatly improved service for the increasing number of people using the line.”


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