With the introduction of S7 Stock, the track, electrical supply, and signalling systems are being upgraded in a programme planned to increase peak-hour capacity on the line by 27 per cent by the end of 2023. A single control room for the sub-surface railway opened at Hammersmith on 6 May 2018, and Communications Based Control (CBTC) provided by Thales will progressively replace 'fixed block' signalling equipment dating back to the 1940s.
