Capacity can be increased further if the operation of the Charing Cross and Bank branches are separated. New S Stock trains are being introduced on the sub-surface (District, Metropolitan, Hammersmith & City and Circle) lines, and the track, electrical supply and signalling systems are being upgraded in a programme planned to increase peak-hour capacity by the end of 2018. A single control room for the sub-surface network is to be established in Hammersmith and an automatic train control (ATC) system will replace signalling equipment installed from the 1940s. Options for new trains for the Bakerloo and Piccadilly lines are being considered. Crossrail is under construction and is now expected to open in 2020, providing a new underground route across central London integrated with the London Underground system. Options are being considered for the route of Crossrail 2 on a north-south alignment across London, with hopes that it could be open by 2033.