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,
Clapham Common tube station Clapham Common tube station Clapham Common is a London Underground station in Clapham within the London Borough of Lambeth. It is on the Northern line, between Clapham North and Clapham South stations, and is in Travelcard Zone 2. The station is at the eastern tip of Clapham Common and was opened in June 1900 as the new southern terminus of the City & South London Railway, which was extended from Stockwell. It remained the terminus until the Morden extension was opened in 1926. The station has two entrances, one at the west via a domed building dating from the 1920s,