|Builder:||Birmingham Railway Carriage & Wagon Company|
|Engine:||Sulzer 8LDA28 diesel|
|Power:||1, 550 hp (1, 156 kW)|
Most Class 33s were in the standard 33/0 sub-class, however a number were also fitted for push-pull operations as 33/1 and operated with the 4-TC (Class 438)  though could also work with any SR Electro-Pneumatically controlled multiple units and locomotives. A batch of locomotives was also reduced in width by 178mm for operation on the Hastings Line with its restricted clearances as the 33/2. Sadly the expense and effort in modifying the design for what turned out to be a small batch of locomotives is said to have contributed to BRCW's bankruptcy in the mid-1960s.
Nowadays only a handful of the locomotives, known as Cromptons by enthusiasts after the Crompton Parkinson electrical equipment installed in them, remain in mainline use with the West Coast Railway Company however 29 have been preserved covering all 3 sub-types.
|33 103 at Wirksworth|
|Cab of 33 103|
|33 204 at Stewarts Lane in 1988, photographer unknown|
|Class 33 undergoing maintenance at Stewarts Lane 1988, photographer unknown|
|33 035 at Kidderminster|
 Brian Haresnape, Production Diesel-Electrics Types 1-3 (Ian Allan, 1983) p. 58
 David Brown, Southern Electric Vol 2 (Capital Transport, 2010) p. 215
 John Vaughan, Diesels on the Southern (Ian Allan, 1980) p. 33