British Rail 18000
From Wikipedia, the free encyclopedia
| British Rail 18000 | |
 18000 at Vienna in 1989 |
|
| Builder: | |
|---|---|
| Weight: | 115 long tons (117 t). |
| Maximum speed: | 90 miles per hour (140 km/h) |
| Operators: | British Railways |
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 1940, 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.
Contents |
[edit] Overview
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. It had a maximum speed of 90 miles per hour (140 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.
[edit] Technical details
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. 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.
[edit] Comparison of 18000 and 18100
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:
- In 18000, output horsepower is 24% of total horsepower and in 18100, output horsepower is 33% of total horsepower. This suggests that 18100 had the higher thermal efficiency but, in practice, 18000 had the higher thermal efficiency. The horsepower figures should, therefore, be regarded with some scepticism.
- Where electric transmission is used, the horsepower of the traction motors is usually 81% (i.e. 90% x 90%) that of the prime mover. The figure for 18100 is therefore about right but the figure for 18000 looks anomalous.
- lbf = pound-force
[edit] Post-BR use
At the end of 1960 it 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.
[edit] Preservation
In the early 1990s it was secured for preservation and returned to the United Kingdom; it is now kept at The Railway Age, Crewe.
[edit] See also
[edit] Sources
- Sampson, H. (editor), The Dumpy Book of Railways of the World, published by Sampson Low, London, date circa 1960
- Robertson, K. The Great Western Railway Gas Turbines, published by Alan Sutton, 1989, ISBN 0 86299 541 8
|
|||||||||||||||||||||||||||||
