Mk IV passenger vehicles for East Coast Main Line electrification

The Class 91 locomotives and Mk IV train sets have been designed for daytime use on services operating at up to 225 km/h. The composition of the train sets was determined by an economic need to make maximum use of the Class 91 locomotives. The Mk IV vehicles are day coaches, the locomotives will also be used at night hauling sleeping car and mail trains at speeds of up to 160 km/h. Improvements were also required in all areas of equipment and the authors set out to cover the design approach adopted to provide a new generation of passenger vehicles