Sleet locomotives were specialised de-icing vehicles for use on open-air sections of the Underground. Eighteen were built at Acton Works during 1939 and 1940. They were constructed out two former 1903 Central London Railway motor cars, back-to-back. The de-icing equipment, including brushes, ice-crushers and spraying gear, was carried by trailer bogies under the central portion. Anti-freeze solution was contained in two 75-gallon tanks.

Sleet locomotives became redundant in the 1980s, when de-icing equipment was fitted to passenger stock.