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
South Wimbledon tube station South Wimbledon tube station South Wimbledon is a London Underground station in South Wimbledon, a suburb of Wimbledon in south-west London. The station is on the Northern line, situated between Colliers Wood and Morden stations. It is located on the corner of Merton High Street (A238) and Morden Road (A219). South Wimbledon is on the boundary between Travelcard Zone 3 and Zone 4. The station was opened on 13 September 1926 as part of the Morden extension of the City & South London Railway south from Clapham Common. On the original plan it had the name "Merton Grove". For geographical