British Rail Class 50

The British Rail Class 50 is a class of diesel locomotives designed to haul express passenger trains at 100 mph (160 km/h). Fifty were built by English Electric at the Vulcan Foundry in Newton-le-Willows between 1967 and 1968, numbered D400 to D449 and known as English Electric Type 4s. Their design descended from the prototype DP2, a 2,700 hp diesel-electric locomotive that English Electric based on its Deltic design but powered by a single 16CSVT engine, a development of the 16SVT used in the Class 40. The locomotives were initially on a 10-year lease from English Electric Leasing and were employed hauling express passenger trains on the then non-electrified section of the West Coast Main Line between Crewe and Scotland. When electrification there was completed they moved to the Great Western Main Line out of Paddington and later to services between London Waterloo and Exeter St Davids. The class gained the nickname Hoovers from the noise of the clean air plant, and it was steadily retired in the late 1980s and early 1990s.