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.
One of the London and South Western Railway's railmotors from the Southsea Railway, was borrowed for trials on the Golden Valley Line at Stroud. This proved successful and two GWR steam rail motors, designed by George Jackson Churchward, 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.
The rail motors not only stimulated traffic on branch lines, where small and cheap platforms could be built to serve small traffic sources, but also in towns such as Plymouth where they operated frequent services in an attempt to fight off competition from new electric tramways. On some services they proved so successful that they could not cope with the number of passengers wishing to travel and so extra coaches were needed, but rail motors could not always cope with pulling trailers on hilly lines. One such example of this was on the Wrington Vale Light Railway where SRM 38 would need to stop on the 1 in 50 gradient to raise enough steam to reach the top, however this sometimes happened without a trailer too.
A fault in the power unit meant the whole train had to be taken out of service. Maintaining the power units in dirty engine sheds made it difficult to to keep clean the passenger sections attached to them.
Most rail motors were converted into autocoaches and the power units were scrapped. Autotrains offered most of the benefits of rail motors but, because they were operated by separate locomotives, were much more flexible in operation and easier to maintain. The first SRM was withdrawn in 1914 but sixty-five survived until 1922 and the last was withdrawn in 1935.
All of the fleet were built with four-wheel vertical-boiler power units and a four-wheel trailing bogie under the carriage. Driving wheels were from 3ft 5in to 4ft (1,041mm to 1,219mm); cylinders were from 9in × 15in to 12in × 16in (229mm × 381mm to 305mm × 406mm).
Some dimensions were ¾ inch larger than shown in this table where figures have been rounded down to nearest inch.
|A, A1||2||1-2||1903||57 feet (17 m)||8.5 feet (2.6 m)|
|B, C, D||12||3-14||1904||59.5 feet (18.1 m)||8.5 feet (2.6 m)|
|E||2||15-16||1905||56 feet (17 m)||9 feet (2.7 m)|
|F, G, G1||12||17-28||1904||59.5 feet (18.1 m)||8.5 feet (2.6 m)|
|H, J, J1||8||29-36||1905||59.5 feet (18.1 m)||9 feet (2.7 m)|
|K, K1||4||37-40||1905||70 feet (21 m)||9 feet (2.7 m)|
|L||2||41-42||1905||59.5 feet (18.1 m)||9 feet (2.7 m)|
|M, M1, N||10||43-52||1905||70 feet (21 m)||9 feet (2.7 m)|
|O||18||53-58, 61-72||1906||70 feet (21 m)||9 feet (2.7 m)|
|P||2||59-60||1905||70 feet (21 m)||9 feet (2.7 m)|
|Q||8||73-80||1906||70 feet (21 m)||9 feet (2.7 m)|
|Q1||3||81-83||1907||59.5 feet (18.1 m)||9 feet (2.7 m)|
|R||16||84-99||1908||70 feet (21 m)||9 feet (2.7 m)|
In February 1908 a steam rail motor was turned out from Swindon railway works and given the number 93. It was one of sixteen built to Diagram R, the last batch of steam rail motors These were 70 feet (21 m) long and 9 feet (2.7 m) wide. After running 479,006 miles (770,885 km) it was withdrawn in November 1934, the power unit removed and the carriage portion converted into an auto trailer. Now renumbered 212, it operated in this form until May 1956. It was then put into use as a "Work Study Coach" and later as an static office in Birmingham.
In 1970 it was sold to the Great Western Society and moved to their base at Didcot Railway Centre but it was not until 1998 that they were able to make a start on returning it to original condition as a steam rail motor. The frame of the new power bogie was erected in November 2000 at the Tyseley Locomotive Works and was then mounted on wheels and fitted with a boiler. In March 2008 the power bogie was put on display at Didcot. In January 2009 it was moved to the Llangollen Railway where the carriage portion was restored and the two portions brought together. Work was completed in 2011 and number 93 has since been operated at Didcot and on various railway lines.
- Maggs, Colin G (2004). The Wrington Vale Light Railway. The Oakwood Press. ISBN 0-85361-620-5.
- Harris, Michael (1966). Great Western Coaches From 1890. Newton Abbot: David and Charles. ISBN 0-7153-8050-8. Text "pages 145-147" ignored (help)
- "Railmotor No. 93". GWR Steam Railmotor and Trailer Project. Retrieved 2013-03-20.
- "The New Power Bogie". GWR Steam Railmotor and Trailer Project. Retrieved 2013-03-20.
- Casserley, HC; Johnston, SW (1966). Locomotives at the Grouping, Volume 4 Great Western Railway. Shepperton: Ian Allan Ltd. ISBN 0-7110-0555-9.
- Davies, F.K. (May 1956) . The Rail Motor Vehicles (etc.). The Locomotives of the Great Western Railway. Part 11. Railway Correspondence and Travel Society. pp. L4–L11. ISBN 0-901115-38-X.
- Davies, F.K. (May 1974). A Chronological and Statistical Survey. The Locomotives of the Great Western Railway. Part 12. RCTS. pp. M120; M124–M125; M127–M128.
- Davies, F.K.; White, D.E. (December 1983). Preservation and Supplementary Information. The Locomotives of the Great Western Railway. Part 13. RCTS. pp. N16–N18; N35. ISBN 0-901115-60-6.
- Davies, Ken (April 1993). Names and their Origins; Railmotor Services (etc.). The Locomotives of the Great Western Railway. Part 14. RCTS. pp. P30–P36; P75; P82–P84. ISBN 0-901115-75-4.
- Lewis, John (2004). Great Western Steam Railmotors: and their services. Wild Swan Publications Ltd. ISBN 1-874103-96-8.
- Parkhouse, Niel; Pope, Ian. "The Rise and Fall of the Steam Rail Motor". Archive (Lightmoor Press) (3): 39–46. ISSN 1352-7991.
|Wikimedia Commons has media related to: GWR steam rail motors|
- The GWR Steam Railmotor Project
- The Great Western Archive - Railmotor Introduction
- History of GWR railmotors and autocoaches
- Encyclopedia of Plymouth History – GWR Railmotor Service