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 City Airport North Circular Road (A406). Also the A13 provides easy access to the M25 motorway, as with the A406 connecting to the M11 motorway. The airport has both a short-term and a long-term car park, both within walking distance of the terminal and a taxi rank outside the terminal door. The airport is served by London Buses services: The express shuttle buses, which formerly ran to various destinations, were withdrawn after the DLR line was built. Until 2006, Silvertown railway station on the North London line served the airport, but it was closed during the construction of Crossrail. When the new