The original LBSCR 1908-09 'SL' fleet of eight 3-car a.c. units had included eight Trailer Firsts (TF) - a level of First-class provision that soon proved to be over-optimistic.  When the a.c. fleet was re-formed in 1910-11, the eight TFs were converted to locomotive-hauled vehicles, with centrally-located lavatory compartments.

In 1930 when, presumably, commercial pressures demanded something rather more up-to-date for longer distance First-class travel, the eight coaches were again converted to form four 2-car d.c. motor units, generally similar to the 2 SL units, to operate the newly-electrified branch line from Wimbledon to West Croydon.

Four of the cars were converted to Driving Motor Brake Composites (DMBC).  Three of the original nine seating bays were replaced by an SR-standard 'front end' with a driving cab, guard's van area and space for the standard MV control gear at the rear of the cab.  The central lavatory was converted back to a seating bay and the two bays at the inner end converted to full-width First-class compartments with a total of 16 seats.  The remaining four bays, linked by a side aisle, were re-upholstered to Third-class standards and seated 33.

The other four cars became Driving Trailer Brake Thirds (DTBT), with two of the original nine seating bays replaced by an LBSCR-style half-width driving cab and guard's compartment.  With the central lavatory converted back to a seating bay, this car provided 58 Third-class seats in seven bays linked by a side aisle.

As with the 2 SL units, the cars retained their original 60ft slotted plate-girder underframes, but the original pressed-steel bogies were replaced by other ex-LBSCR trailing bogies and new standard Central Section motor bogies with MV339 motors.  Standard side buffers and screw couplings were retained throughout.

Originally numbered 1909-1912, the units were renumbered 1809-1812 in 1934.

In service

As with the 2 SL units, the 2 Wim fleet was limited by the 9ft 6in overall width of its cars to the Wimbledon-West Croydon route, the South London line and associated routes to depots.  Their lives were uneventful; the only change was the conversion of the First-class compartments to Third-class from 1941.

By 1951 the loss of 2 SL units 1807 and 1802 left the South London line service short of units, resulting in occasional appearances of 1809-1812 on the South London Line.

The units were withdrawn in 1954 and replaced by new BR-designed 2EPB units of the 57xx series.