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
Suicide on the London Underground inform the public), "person on the track", "passenger action," but most commonly "one under", or "jumper" — well-known phrases across the network. Those who survive are often charged with offences such as "endangering safety on the railway" and "obstruction of trains with intent". About half of the stations, mostly those actually underground, have a pit under the tracks. Originally constructed to drain water, they have now been shown to reduce the number and severity of injuries and deaths, although not to eliminate them: as a Transport for London (TfL) spokesperson has said, "people fall into [the pits] and the train