The British Rail Class 86 was the standard electric locomotive built during the 1960s, developed as a result of testing with the earlier Classes 81, 82, 83, 84 and 85. One hundred of these locomotives were built from 1965-1966 by either English Electric at Vulcan Foundry, Newton-le-Willows, or British Rail (BR) at their Doncaster works. The class was built to haul trains on the then newly electrified West Coast Main Line, from London Euston, to Birmingham, Crewe, Manchester Piccadilly, Liverpool and later Preston and Glasgow. They helped to replace steam locomotives, which were finally withdrawn by BR in 1968. Under the earlier BR classification, the type was given the designation AL6 (meaning the 6th design of AC Locomotive), and locomotives were numbered E3101-E3200. In 1968, this was changed to Class 86, when BR introduced the TOPS classification system. In the early years the locomotives became notorious for track damage, being fitted with axle-hung traction motors, in place of the bogie-frame-mounted motors of the earlier designs. This additional unsprung mass was causing damage at high speeds. In 1969 number E3173, was fitted experimentally with the large helical 'flexicoil'