The British Rail Class 91 is a high-speed electric locomotive, which produces power of 4,830 kW (6,480 hp); it was ordered as a component of the East Coast Main Line modernisation and electrification programme of the late 1980s. The Class 91s were given the auxiliary name of InterCity 225 to indicate their envisaged top speed of 225 km/h (140 mph); they were also referred to as Electras by British Rail during their development and throughout the electrification of the East Coast Main Line. The other end of the InterCity 225 train set is formed of a Mark 4 Driving Van Trailer, built with a similar body shell to the Class 91 locomotives but with only one driving cab. The locomotive body shells are of all-steel construction. Unusually, the motors are body mounted and drive bogie-mounted gearb