British Rail 18100

British Rail 18100 was a prototype main line gas turbine–electric locomotive built for British Railways in 1951 by Metropolitan-Vickers, Manchester. It had, however, been ordered by the Great Western Railway in the 1940s, but construction was delayed due to World War II. It spent its working life on the Western Region of British Railways, operating express passenger services from Paddington station, London.

The locomotives basic parameters were stipulated by then chief mechanical engineer of the Great Western Railway. These requirements were that it should be suitable for hauling the heaviest passenger trains on the Western main routes, particularly that between London and Plymouth, and at speeds up to 90 m.p.h.

This needed a maximum starting tractive effort of the order of 60,000 lb and, with the stipulated maximum axle loading, that requires six driving axles. The same considerations led to fixing the continuous rating at 30,000 lb tractive effort. Electric transmission was adopted as the only practicable and reliable means of satisfying these conditions.