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
Attacks on the London Underground Attacks on the London Underground This is a list of deliberate attacks on the infrastructure, staff or passengers of the London Underground that have caused considerable damage, injury or death. On 30 October 1883, two bombs planted as part of the Fenian dynamite campaign exploded on the "Inner Circle". The first bomb, planted on a train, exploded near Paddington (Praed Street) station damaging the train it was on and a passing train along with part of the station and the signal box. Sixty-two passengers were injured. At the same time, the second bomb exploded in the tunnel between Charing Cross