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 GN&C Stock Heath. These plans were curtailed by World War II and the Northern City line (or "Highbury Branch") continued operating with 1938 Stock until 1975, when the line was transferred to British Rail. Since 1976 the line has been operated exclusively by British Rail Class 313 electric multiple units. London Underground GN&C Stock The GN & C Stock was operated on the Great Northern and City Railway, an underground railway line in London, England. It was opened between Moorgate and Finsbury Park on 14 February 1904. The original GN&C Stock operated on the line between 1904 and 1939. The line was