General Motors EMD / Alstom

'General Motors EMD / Alstom' is used in this encyclopedia for the partnership between General Motors' Electro-Motive Division (EMD) — one of the most prolific diesel locomotive manufacturers in the world — and Alstom for the Class 66 and Class 67 diesel-electric locomotives supplied to British freight operators from 1998, locomotives that transformed the economics and performance of British heavy freight operation and which remain the dominant British freight locomotive type.

The EMD 710 prime mover, a 12-cylinder two-stroke diesel, had been developed for the North American freight market where its rugged reliability, standardised components, and ease of maintenance made it the dominant locomotive engine type on American Class 1 railroads. When English Welsh & Scottish Railway (EWS) sought a high-powered, reliable, and economical freight diesel to replace the ageing BR Class 37, 47, and 56 fleets inherited at privatisation, the Class 66 built on the EMD platform — assembled initially at GM's London, Ontario plant — offered advantages of proven reliability and international parts support that no British or European alternative could match.

250 Class 66s were eventually supplied to EWS alone, with further batches going to Freightliner, Direct Rail Services, and other operators, making the Class 66 the largest single-type order for diesel locomotives in British railway history since the BR Standard classes. The Class 67 — a higher-speed variant capable of 125 mph — was supplied for passenger charter and mail train work. Alstom's involvement related to European market compliance and certain secondary systems. The Class 66's dominance of British freight operation has proven extraordinarily durable; more than 500 are in service and the type shows no sign of early retirement despite being a fundamentally 1990s design.