These locomotives were originally built at Crewe from 1987 to 1990 for express passenger use on the West Coast Main Line. Displaced by the “Pendolino” trains they now operate London – Norwich express services with Mk3 coaches and DVTs as push-pull sets using the TDM multiple working system. The TDM system uses the train lighting circuits so no train wiring is required. 50 locomotives were built, the remainder of the class being used on freight duties and belonging to EWS. A continuous rating of 3730 kW ( 5000hp) gives good performance on freight or passenger work, their versatility being helped by separately excited traction motors. Electrical equipment is GEC thyristor control driving four G412CY frame mounted traction motors.