| British Rail 18000 | |
|---|---|
| 18000 at Vienna in 1989 | |
| Power type | Gas turbine-electric |
| Builder | Brown, Boveri & Cie and Swiss Locomotive and Machine Works |
| Order number | GWR Lot 372 |
| Serial number | BBC: 4559 SLM: 3977 |
| Build date | 1949 |
| UIC classification | (A1A)'(A1A)' |
| Driver diameter | 4 ft ¼ in (1,226 mm) |
| Trailing wheel diameter |
3 ft 2 in (965 mm) |
| Locomotive weight | 115.18 long tons (117.03 t) |
| Prime mover | Gas Turbine |
| Traction motors | Four |
| Transmission | DC generator DC traction motors |
| Top speed | 90 mph (145 km/h) |
| Power output | 2,500 hp (1,900 kW) |
| Tractive effort | 31,500 lbf (140,000 N) |
| Train heating | Steam generator |
| Career | British Railways |
| Power class | BR: 4 |
| Nicknames | Kerosene Castle |
British Rail 18000 was a prototype mainline gas turbine-electric locomotive built for British Railways in 1949 by Brown, Boveri & Cie. It had, however, been ordered by the Great Western Railway in 1946,[1] but construction was delayed due to World War II. It spent its working life on the Western Region of British Railways, operating express passenger services from London Paddington station.
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The GWR chose a gas-turbine locomotive because, at the time, there was no single-unit diesel locomotive of sufficient power available. The King class steam locomotive could deliver about 2,500 horsepower (1,900 kW) at the rail. The LMS diesel locomotives had engines of only 1,600 hp (1,200 kW). After allowing for transmission losses, this would be down to about 1,300 hp (970 kW) at the rail, so two diesels would be needed to match a King.
No. 18000 was of A1A-A1A wheel arrangement and its gas turbine was rated at 2,500 hp (1,900 kW). It had a maximum speed of 90 miles per hour (145 km/h) and weighed 115 long tons (117 t). It was painted in BR black livery, with a silver stripe around the middle of the body and silver numbers.
The gas turbine was a Brown Boveri industrial machine. It was of a type which would now be called a turboshaft engine but differed from modern turboshaft engines in having only one turbine to drive both the compressor and the output shaft. The emphasis was on fuel economy so it had a heat exchanger (to recover waste heat from the exhaust) and was designed to run on cheap heavy fuel oil (it was also able to burn light oil but this was intended only for startup purposes). This was the same fuel that was used in oil-fired steam locomotives. After leaving the heat exchanger, the pre-heated air entered a large, vertical, combustion chamber where the fuel was injected and burned.
There was also an auxiliary diesel engine which provided power for starting the gas turbine. The diesel engine was capable of moving the locomotive at a slow speed when the gas turbine was not running. The usual procedure was to run the locomotive from the shed to Paddington station using the diesel engine and to start the gas turbine only a few minutes before the train was due to leave. This saved fuel and minimised annoyance from noise and exhaust fumes.
It proved a troublesome machine in service. Ash from the heavy fuel oil damaged the turbine blades, and the combustion chamber liner required frequent replacement due to damage. The electrical control systems were extremely complex for the time and gave much trouble; maintenance of the electrical equipment in a steam locomotive environment and knowledge base was difficult. Part way through its life one of the traction motors failed and instead of repairing or replacing it, it was simply removed, leaving the locomotive with only three traction motors and preventing it from achieving its full power output. It also suffered from the destruction of its heat exchanger in a fire at Temple Meads when combustion deposits in the exhaust side of the heat exchanger ignited.
It was also heavier than expected in fuel costs. The efficiency of a gas turbine reduces dramatically at low power outputs so to achieve respectable fuel economy a gas turbine locomotive needs to be operated as much as possible at full power, with periods of part-load running reduced to a minimum. However, it turned out that even on demanding express passenger schedules it was not possible to operate the locomotive on full power for very much of the run and extended periods of part-load operation were inevitable, which resulted in heavy fuel consumption. It was also sometimes fuelled on the much more expensive and scarce light oil normally used only for starting, due to the level of wear caused by the ash from heavy fuel oil.
When reliable operation could be achieved, it did show itself capable of meeting expectations. Unfortunately, however, it was neither possible to achieve an acceptable level of reliability nor to operate it under conditions which would allow reasonable fuel economy.
The following table gives a comparison between 18000 and 18100. There are some anomalies and these are described in the notes.
| Value | 18000 | 18100 | Notes |
|---|---|---|---|
| Weight (tons) | 115 | 129 | - |
| Turbine horsepower | 10,300 | 9,000 | (1) |
| Power absorbed by compressor | 7,800 | 6,000 | (1) |
| Output horsepower | 2,500 | 3,000 | (1) |
| Number of traction motors | 4 | 6 | - |
| Total traction motor horsepower | 2,500 | 2,450 | (2) |
| Starting tractive effort (lbf) | 31,500 | 60,000 | (3) |
Notes:
At the end of 1960 18000 was withdrawn from operation and was stored at Swindon Works for four years. It then returned to mainland Europe, where for more than ten years it was used, in substantially altered (and no longer gas-turbine-powered) form, for experiments concerning the interaction between steel wheels and steel rails, under the auspices of the International Union of Railways. In 1975 it was moved to Vienna and displayed outside the Mechanical Engineering Testing building.
In the early 1990s it was secured for preservation. It returned to the UK and was kept at The Railway Age, Crewe. It was then moved to Barrow Hill Engine Shed and was repainted in green livery.
In mid-April 2010 it was delivered to the Gloucestershire Warwickshire Railway in order to take part (as a static exhibit) in the celebrations for the 175th birthday of the Great Western Railway from 29 May to 6 June 2010.
Since then, it has moved to Didcot. It arrived at the yard, west of Didcot Parkway railway station, on 20th July 2011 and was moved into Didcot Railway Centre on 29th July 2011. It is now owned by the Pete Waterman Trust.[2]
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