Portal:Trains/Selected article/Week 25, 2013

Departmental locomotives on the London Underground consist of vehicles of a number of types which are used for engineering purposes. These include battery locomotives, diesel locomotives, electric locomotives, sleet locomotives, pilot motor cars and ballast motor cars. Pilot motor cars and ballast motor cars are generally vehicles which have been withdrawn from passenger service, but continue to be used by the engineering department. Pilot motor cars are used to move other vehicles around the system, while ballast motor cars are used to haul ballast trains and engineering trains. The first ballast motor cars were former trailer cars built for the Central London Railway in 1900, which were converted to motor cars for trials of the first multiple system to be used in Britain, and were retained for departmental use after 1903. These were followed by French and Hungarian Gate stock cars, built in 1906, which were converted in the 1920s and 1930s. The next batch consisted of 14 standard stock cars converted in 1953. Rolling stock reorganisation and replacement in the 1970s on the District and Metropolitan lines resulted in a number of surface stock cars being used for pilot motor duties. Subsequently motor cars of 1938 stock and 1960 stock were used for this purpose, and complete 4-car units of 1962 stock. The London Underground has also owned several departmental self-powered vehicles designed for other duties. These include a tunnel cleaning train, consisting of two 1938 stock motor cars and three purpose-built cars, which act like a giant vacuum cleaner, and can hold 6 tons of dust before the filter tanks need to be emptied. Three Plasser & Theurer track tamping machines were purchased in 1980, and two Unimog road-rail vehicles were obtained in 1983 and 1986, for use as depot shunters.