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
London Underground A60 and A62 Stock stock. London Underground A60 and A62 Stock The London Underground A60 and A62 Stock was a type of sub-surface rolling stock which operated on the Metropolitan line of the London Underground from 12 June 1961 to 26 September 2012, and on the East London Line from 1977 until 22 December 2007, when it closed to be converted into London Overground (except in 1986, when one person operation conversion of the fleet took place). The stock was built in two batches (A60 and A62) by Cravens of Sheffield in the early 1960s, and replaced all other trains on the line. At