London Underground with smaller trains that run in two circular tunnels ("tubes") with a diameter about . These lines have the exclusive use of a pair of tracks, except for the Piccadilly line, which shares track with the District line between Acton Town and Hanger Lane Junction and with the Metropolitan line between Rayners Lane and Uxbridge; and the Bakerloo line, which shares track with London Overground services north of Queen's Park. Fifty-five per cent of the system runs on the surface. There are of cut-and-cover tunnel and of tube tunnel. Many of the central London underground stations on deep-level tube routes
London Underground 2009 Stock FICAS technology, giving a thinner bodyshell and hence (along with the larger size) more internal space for passengers. They are the first London Underground trains to be designed since the Rail Vehicle Accessibility Regulations were introduced, so they have more facilities for people with impaired mobility, including multi-purpose areas with tip-up seats and space for wheelchairs and pushchairs, and offset centre door poles for wheelchair access. The trains were the longest deep-level tube trains on the system when introduced, at , longer than the 1967 Stock. The more recently introduced sub-surface S Stock, which is also part of Bombardier's Movia