Sleet locomotives were redundant London Underground cars converted to help with the removal of ice that built up on the conductor rails. The main batch of eighteen tube-gauge locomotives were built between 1938 and 1941 from motor cars originally built in 1903. They were refurbished in the 1960s using equipment removed from redundant T-stock vehicles, and were joined by a pair of surface-gauge locomotives in 1961. In addition to de-icing duties, some of them were also used for experiments in clearing leaves from the running rails. They had all ceased to operate by 1985. One of the tube-gauge locomotives subsequently went to the London Transport Museum, and the surface-gauge cars went to the Spa Valley Railway.