Masterclass
BEN JONES pieces together the little-known story of five Brush Type 4s built with French Sulzer V12 engines in the mid-1960s.
Looking at railways in detail
With 512 locomotives built at two locations over a six-year period, it was inevitable that BR’s ‘standard’ Type 4 Co ‐Co diesel would be anything but standard. Electrical systems and components, train heating equipment, cooling arrangements, axle design, brake systems and various external details varied significantly across the fleet.
However, unlike many other first-generation BR diesels, there was no policy of ‘dual sourcing’ with the Brush Type 4s. Intended as an insurance policy against unsuccessful equipment, dual sourcing helped British industry by distributing lucrative contracts more widely, but weakened the benefits of standardisation.
A proposal to fit part of the Brush Type 4 fleet with English Electric power units and electrical equipment was rejected by BR management and as a result all 512 locomotives were outshopped with Swiss-designed Sulzer engines. Within that group, just five locomotives deviated from the standard 12LDA28C twin-bank power unit – originally good for 2,700hp but downrated in the 1960s to 2,580hp after various weaknesses emerged. The exceptions were D1702 ‐06, built at Brush’s Falcon Works in Loughborough and delivered between September 1965 and July 1966. Ordered in September 1962, the five locomotives were delivered much later than the rest of their batch, which was accepted by the Eastern and Western Regions between October 1963 and January 1964.
The reason for the lengthy delay to the quintet was the experimental fitting of Sulzer 12LVA24 engines – a French-built V12 power unit rated at 2,650hp. Numerous internal modifications had to be made to accommodate the Vee-type engine, although th
