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The GWR Autocoach (or auto-trailer) is a type of coach that was used by the Great Western Railway for push-pull trains powered by a steam locomotive. The distinguishing design feature of an autocoach is the driving cab at one end, allowing the driver to control the train without needing to be located in the cab of the steam locomotive. This eliminates the need to run the engine round to the other end of the coach at the end of each journey.
Contents
When one or more autocoaches are connected to a suitably equipped steam locomotive, the combination is known as an auto-train, or, historically, a railmotor train. A steam locomotive provided with the equipment to be used as an autotrain is said to be auto-fitted.
The autocoach is the forerunner of the driving trailer used with push–pull trains.
Design features
A locomotive fitted with additional control equipment is used to power the autotrain.
When running 'autocoach first', the regulator is operated by a linkage to a rotating shaft running the length of the locomotive, passing below the cab floor. This engages (via a telescopic coupling) with another shaft running the full length below the floor of the autocoach. This shaft is turned by a second regulator lever in the cab of the autocoach. (See photograph sequence below.) The driver can operate the regulator, brakes and whistle from the far (cab) end of the autocoach; the fireman remains on the locomotive and (in addition to firing) also controls the valve gear settings. The driver can also warn of the train's approach using a large mechanical gong, prominently mounted high on the cab end of the autocoach, which is operated by stamping on a pedal on the floor of the cab. The driver, guard and fireman communicate with each other by an electric bell system.
Internally, the passenger section of the coach is divided into two open saloons – originally for 'smoking' and 'non-smoking' – with a lobby in the middle separating the two. There is usually a small guard's and luggage compartment at the 'loco' (non-driving) end of the coach. The seating layout is similar to the lower deck of a modern-day bus, with a mixture of normal seating and inwards-facing bench seats. Passengers access the coach via the lobby. The coach is equipped with retractable steps, which are extended if the train stops at rural 'halts' with either low or non-existent platforms, and which fold-in tight against the coach underframe to keep them clear of lineside obstructions when the train is moving. These steps are controlled by the guard using levers in the lobby.
Some earlier autocoaches were converted from steam rail motors, by the removal of the integral steam engine. The most familiar type of autocoach was introduced in 1928. The design proved very long-lived, with 163 examples being built to a similar design. The last coaches were built some years after nationalisation by British Railways in 1954.
In operation
If more than one autocoach was used, the locomotive would usually be marshalled between the coaches, as 'play' in the control linkages could otherwise make operation difficult. This arrangement was not always possible where turntables were not convenient for turning coaches and hence up to two autocoaches could follow or lead a locomotive with cab ends away from the locomotive.
When used on rural branch lines these coaches were normally paired with a 517 or, after 1932, 4800/1400 Class 0-4-2 tank locomotive; some 0-6-0 pannier tanks were also fitted for autotrain working. Autocoaches were also used on some main-line duties; a famous one being that between Gloucester and Chalford on the Golden Valley Line route between Gloucester and Swindon. They could also be found on some London inner-suburban services out of Paddington, where they were usually powered by the faster and more powerful 5400 Class 0-6-0 pannier tanks. Auto-trains on the steeply graded routes in the South Wales valleys often used the smaller-wheeled 6400 Class engines.
Accidents and incidents
Auto-fitted locomotives
Several locomotive classes included examples equipped to work in autotrains at different times. These included:
In fiction
In The Railway Series No.23, Enterprising Engines, four former GWR autocoaches, named Isabel, Dulcie, Alice and Mirabel, are saved from scrap and brought to the fictional North Western Railway to work on the Tidmouth-Arlesburgh branch line there with ex-Great Western tank engines, Duck and Oliver. However they do not appear in the television series based on the books.