Is there a specific date on which TfL plans to bring the new signalling system for the Four Lines Modernisation Programme into service?

The Four Lines Modernisation Programme (4LM) is delivered by progressively installing new signalling onto sections of the railway called signal migration areas (SMAs).

The fifth section of signalling between Sloane Square, Paddington, Fulham Broadway and Barons Court, called Signalling Migration Area 5 (SMA5), went live on 27 March 2022. This allows a new timetable to be introduced in September 2022, which will enable a journey time improvement of around five per cent on average on the Circle and District lines between Monument, Fulham Broadway, Barons Court and Paddington. This follows journey time improvements of up to 10 per cent on the north side of the Circle line in September 2021, enabled by the successful installation of previous sections of new signalling.

SMA5 was a major achievement as it involved upgrading the highly complex junction at Earl’s Court and completed the switch to new digital signalling across the entire Circle line. It also means that the Metropolitan, District and the Hammersmith & City lines are all operating under the new signalling in the central area.

Software development continues for future signalling migration areas covering the eastern end of the District line and the Metropolitan line between Finchley Road and Preston Road, including the interface with Neasden Depot and the Jubilee line. Transport for London (TfL) expects to complete a review of the 4LM programme by end of July 2022, at which time a further update will be available. I have asked TfL to keep you updated.