Circle line (London Underground) with the other London Underground sub-surface lines: the Hammersmith & City line from Hammersmith to just before Aldgate; the Metropolitan line from Baker Street to Aldgate; and the District line from Tower Hill station to Edgware Road station. The line is electrified with a four-rail DC system: a central conductor rail is energised at and a rail outside the running rail at , giving a potential difference of . The running rails are not electrified. Much of the double track railway from the Hammersmith terminus to Westbourne Park station is on a high brick viaduct. East of Westbourne Park the
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