SR Class CW

The Southern Railway (SR) gave the designation CW to the fleet of AC electric multiple units used on the lines to Coulsdon and Wallington. They were planned by the London, Brighton and South Coast Railway but were delayed by the World War I and the grouping and were introduced by the Southern Railway.

Construction
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 stock, built by the Metropolitan Carriage, Wagon and Finance Company at Birmingham, was as follows: The Motor Luggage Vans (nicknamed "Milk Vans") each had four 250 horsepower (190 kW) GEC traction motors.
 * 21 Motor Luggage Vans
 * 60 Driving Trailers
 * 20 Trailers

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.