Testing of the new signalling system to be introduced by Thales and London Underground as part of the Four Line Modernisation (4LM) scheme has reached the point where a train is running at LU’s line speed of 50mph.

LU also hopes that the Automatic Train Operation (ATO) system could be in place around 18 months earlier than the planned 2023 introduction date.

When the scheme is completed there will be 33% more trains on the Circle, District, Hammersmith & City and Metropolitan Lines. District Line capacity will increase by 24%, the ‘Met’ Line will increase by 27%, and the Circle and Hammersmith & City Lines will jointly increase by 65%.

Thales signed a £760 million deal with LU last year. This replaced a deal Transport for London had agreed with Bombardier for the system in 2011, at a cost of £345m. TfL said at the time that that deal was “not progressing”.

While testing is under way at Old Dalby, LU Sub-Surface Programme Director Stuart Harvey said that Bombardier was fitting the second S-Stock train with the signalling equipment at Derby Litchurch Lane. This was the first ‘factory-fit’ train, he said.