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,
Southwark tube station of high floor in the central area of the tunnel, from where narrow tube-like escalator shafts lead sideways (south) to the higher concourse. The upper concourse is the centrepiece of the station. It is a space high with a glass roof that allows daylight to enter deep into the station. It is faced with a spectacular glass wall, long, consisting of 660 specially cut pieces of blue glass, which was designed by the artist Alexander Beleschenko. The wall is one of the extension's more celebrated architectural features, winning critical approval and a number of awards. MacCormac said the design of