History of the London Underground and was followed by 1959 tube stock. After experiments with an AEC lightweight diesel multiple unit in 1952, steam trains were removed from the Central line following the electrification of the Epping–Ongar section in 1957. Between 1963 and 1970, London Transport reported directly to the Minister of Transport, before control passed to the Greater London Council. Electrification work on the Metropolitan line, suspended due to the war, had restarted in 1959. The line was electrified to and the unpainted aluminium (A Stock) replaced steam trains, British Rail providing services for the former Metropolitan line stations between Amersham and . The
London Underground and the mechanisms are regularly degreased to lower the potential for fires. The only wooden escalator not to be replaced was at Greenford station, which remained until October 2015 when TfL replaced it with the first incline lift on the UK transport network. There are 426 escalators on the London Underground system and the longest, at , is at Angel. The shortest, at Stratford, gives a vertical rise of . There are 184 lifts, and numbers have increased in recent years because of investment making tube stations accessible. Over 28 stations will have lifts installed over the next 10 years,