The century-old Hammersmith Depot, in west London, is not well-suited to maintaining the heavily-used trains of the modern London Underground. A brick wall next to the depot’s lifting road – the track equipped with gear to lift carriages off their wheels for maintenance – gives workers little room to move. The lifting road building is only just long enough to handle a two-carriage unit of C Stock, as the 30-year-old trains the depot maintains for the underground’s Circle, Hammersmith & City and District Lines are known.

The constraints on the depot – and its significance for some of the underground’s most intensively-used lines – have made it a testing ground for management techniques introduced by both Metronet – the private company that now operates Hammersmith depot – and Tubelines, the other private consortium involved in maintaining underground track and trains.