Routemaster - Design

Design

The Routemaster bus was developed in 1947–1956 by a team directed by A. A. M. Durrant and Colin Curtis, with vehicle styling by Douglas Scott. The design brief was to produce a vehicle that was lighter (hence more fuel efficient) and easier to operate and that could be maintained by the existing maintenance practices at the recently-opened Aldenham Works. The resulting vehicle seated 64 passengers despite being three-quarters of a ton lighter than the RT family, which seated 56. The first task on delivery to service was to replace London's trolleybuses, which had themselves replaced trams, and to begin to replace the older types of diesel bus. The Routemaster was intended for London use, being designed by London Transport and constructed at the bodybuilder Park Royal Vehicles, with the running units provided by its sister company AEC. (Note: Associated Commercial Vehicles owned both AEC and PRV.)

It was an innovative design and used lightweight aluminium and techniques developed in aircraft production during World War II. As well as a novel weight-saving integral design, the Routemaster also introduced for the first time on a bus independent front suspension, power steering, a fully automatic gearbox and power-hydraulic braking. This surprised some early drivers, who found the chassis unexpectedly light and nimble compared with older designs, especially as depicted on film on tests at the Chiswick Works "skid pan". Footage of RM200 undergoing the skid test at Chiswick was included in the 1971 film On the Buses.

The Routemaster was a departure from the traditional chassis/body construction method. It was one of the first "integral" buses, with a combination of an "A" steel sub-frame (including engine, steering and front suspension) and a rear "B" steel sub-frame (carrying rear axle and suspension), connected by the aluminium body. The gearbox was mounted on the underside of the body structure with shafts to the engine and back axle.