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
Urban rail in the United Kingdom example Amersham and , but some stations much closer to the Greater London boundary, like and , are not in any zone. London has an integrated ticketing system via the Travelcard or Oyster Card for buses, Docklands Light Railway, suburban rail, tram, Underground and Overground. Unlike cities like Liverpool/Merseyside, Sydney and Paris, several operators provide suburban rail services. Most stations are served at least every 20 minutes, with many stations and routes having four, six or more trains per hour. c2c runs from London Fenchurch Street through east London via Basildon (or Grays and Tilbury) to Southend Central and Shoeburyness,