The CW (Coulsdon and Wallington stock) units were built in 1923–1924, as the last electric train stock for use on the LBSCR AC overhead electrified lines in South London. This stock comprised some hundred carriages, which were used in five-car formations: Driving Trailer Third (DTT) + Driving Trailer Composite (DTC) + Motor Luggage Van (MLV) + Trailer Composite (TC) + Driving Trailer Third (DTT).
The Motor Luggage Vans (nicknamed "Milk Vans") each had four 250 horsepower (190 kW) GEC traction motors.
After the replacement of the AC overhead equipment by the 660 V DC third rail system adopted as standard by the SR, the carriages that formed these units were rebuilt accordingly, the Motor Luggage Vans becoming bogie goods train brake vans.
References
Gould, David (1995). Bogie Carriages of the London, Brighton and South Coast Railway. Headington, Oxford: The Oakwood Press. pp. 168–190. ISBN0-85361-470-9.
Marsden, Colin J. (1983). Southern Electric Multiple-Units 1898–1948. Shepperton, Surrey: Ian Allan Limited. pp. 11–13, 92. ISBN0-7110-1253-9.