GWR steam rail motors

The steam rail motors (SRM) were self-propelled carriages operated by the Great Western Railway in England and Wales from 1903 to 1935. They incorporated a steam locomotive within the body of the carriage.

In the first years of the twentieth century, railway managements turned their attention to the need to provide better local passenger services and to reduce costs, in the face of increasing demand for convenient travel and the competitive threat posed by urban tramways.

The original strengths of railways—a fixed track, multiple vehicle passenger trains, highly structured and staffed stations—had limitations in responding to changing needs. The London and South Western Railway had successfully operated a railmotor, consisting of a self-contained passenger vehicle with its own steam power unit, on its Southsea Railway, and the Great Western Railway arranged to borrow one unit for trials on its Golden Valley Line in Gloucestershire. The trial proved successful and a steam rail motor was designed by the Chief Mechanical Engineer George Jackson Churchward. Two units were manufactured, and they entered service on the same route on 12 October 1903. A further 44 were built during 1904 and 1905 and by the time production finished in 1908 the fleet numbered 99 carriage units. There were 112 power units which could be changed between carriages to suit maintenance needs.

On this rural route with a scattered population along the rail corridor, the new vehicles enabled a more frequent service to be operated at lower cost. Stops were made at new locations, and passengers joined and left the train at cheap and simple ground-level platforms using power operated steps on the vehicles. Six new stopping places were provided between Chalford and Gloucester for this service. The guard issued tickets on the train, avoiding the need for staffing at the halts. The vehicles could be driven from either end, so time was not lost in running round at terminals.

The rail motors were also deployed in cities such as Plymouth, where they operated frequent services calling at new stopping places, competing with the new electric tramways.

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Wikipedia