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.