Class 33

The Southern Railway had invested heavily in electrification of their suburban network and expansion continued under British Railways. As steam traction was being replaced by diesel the Southern region needed a locomotive suitable for goods services and compatible with its' electric trains, particularly delivering electric power in place of steam for train heating. Eliminating the steam generator allowed the Birmingham Railway Carriage and Wagon company to offer the 8-cylinder 1,550bhp Sulzer LDA diesel engine inside the existing body designed for it's type 2 class 26/27 locomotives, along with an auxiliary generator for electric train heating supply. The additional horsepower was welcome for freight service and helped offset the power used for heating passenger trains. Not only have the Sulzer LDA engines proven highly reliable but BRCW built very good locomotives, as proven by the long working lives of the 26, 27 and 33 classes. The 33s have long been known as 'Cromptons' by Southern men from their Crompton-Parkinson electrical machinery, though elsewhere the Derby class 45s were 'Cromptons', for the same reason!
Although based on the Southern class 33 locomotives were not restricted to Southern routes, even from new the locomotives regularly worked goods trains through to destinations, with a regular cement train to Doncaster. By the 1980s 33s had taken over the Cardiff-Portsmouth cross-country passenger services. This route brought the locomotives to Bristol and South Wales and after class 50 locomotives released more 33s from the Southern route to Exeter line  regular workings from Cardiff took them to West Wales, Crewe and Manchester, often with a 5 coach set of Mk.1 stock, a train which can nicely be replicated in model form.

A small number of class 33s remain registered for operation on Network Rail, mostly with the railtour operator West Coast Trains, along with one Swanage Railway locomotive registered for working to Wareham, one of 25 examples serving on heritage railways.