SR Class SL
The Southern Railway (SR) gave the designation SL to the fleet of AC electric multiple units used on the former London, Brighton and South Coast Railway South London Line.
Construction
The SL (South London stock) units were built in 1909 for use on the LBSCR AC overhead electrified lines in South London. This stock comprised eight three-car units, originally formed Driving Motor Third + Trailer First + Driving Motor Third. They were built by the Metropolitan Amalgamated Carriage & Wagon Company at Birmingham and each motor coach had four 115 horsepower Winter Eichberg motors.
The Trailer First cars were later removed and used as locomotive-hauled stock, from when the driving cars were paired with former loco-hauled coaches converted to Driving Trailer cars.
After the replacement of the AC overhead equipment by the standard SR 660 V DC third-rail system, these units were rebuilt. The Driving Motor cars were paired together again to form eight units designated 2SL. The Trailer First cars (which had been out of EMU stock for nearly twenty years) were included in this programme, and were rebuilt into Driving Motor and Driving Trailer pairs to form four units designated 2Wim, for use on the Wimbledon-West Croydon line.