BR standard class 8 71000 Duke of Gloucester
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British Railways (BR) standard class 8 number 71000 and named Duke of Gloucester is a preserved British steam locomotive. It was built in Crewe Works in 1954 as the prototype for an intended class of high-performance express passenger locomotives. As with the other BR Standard locomotive types, it was designed by the Railway Executive's design committee headed by Robert Riddles.
Although an impressive-looking machine, the locomotive (as originally built) was not a success, and this - along with the later decision to 'dieselise' BR - meant that no more of the type were ever built, so 'The Duke' remained the sole member of its class.
Mechanically, 71000 was a 3-cylinder development of the visually-similar 'Britannia' class locomotives. Its construction was authorized as a replacement for the short-lived 46202 'Princess Anne' (itself a rebuild of 'The Turbomotive') which was destroyed in the Harrow and Wealdstone rail disaster of 1952.
71000 was built with poppet valves and the novel, shaft-driven British Caprotti valve gear. This allowed precise control of steam admission to the cylinders, and gave improved exhaust flows and boiler draughting characteristics compared to the more conventional Walschaerts or Stephenson valve gear.
However, fundamental design errors and undetected deviations from the drawings were made during construction, which combined to prevent 'The Duke' from ever achieving its expected performance in BR days. It was very unpopular with crews, who regarded it as something of a liability due to its poor steam production. This contributed to the locomotive having a short service life (1954 to 1962), spending much of its life hauling boat trains on the undemanding North Wales Coast Line between Crewe and Holyhead.
Having had one of the original outside cylinders removed for display at the Science Museum in South Kensington, London (the other outside cylinder was removed to restore balance) the sad hulk of this unloved locomotive then languished for many years in Woodhams' Scrapyard in South Wales, before an ambitious restoration effort began in 1973. With so many major components missing, it took 13 years of effort - and much help and goodwill from industry - to return the locomotive to working order.
Two significant construction errors were discovered during restoration:
- The chimney was too small compared to other locomotives of similar size, resulting in poor boiler draughting at times of high steam demand.
- The firebed (grate) air inlet dampers had not been built to the drawings, and were too small, resulting in poor oxygen supply and inefficient combustion.
These were corrected, and the opportunity taken to incorporate some other improvements (such as a 'Kylchap' exhaust system) which unlocked the locomotive's true potential. When 71000 was first allowed its head with a full load on the main line, it became immediately obvious that the boiler was now producing steam at a furious rate, and that the re-born 'Duke' was a very different engine from the 'flop' of BR days.
With these modifications, 71000 is now the most powerful steam locomotive ever to run on UK railways past or present, a short head in front of its close ancestor the LMS Princess Coronation Class.
Ironically, 'The Duke' is now more powerful than the English Electric Type 4 diesel locomotives which replaced it in service.
As the locomotive is no longer 'authentic', it has also been used as something of a 'test bed', and now incorporates several other modifications and innovations intended to investigate just how much enhanced performance the locomotive would have been capable of, had history been different.
71000 returned to the UK main lines in 2004 after a major overhaul, and can now be regularly seen hauling enthusiasts' special trains around the country.
[edit] Sound
[edit] References
- A Detailed History Of BR Standard Steam Locomotives. Volume 1. Background to Standardisation and Pacific Classes Railway Correspondence & Travel Society (RCTS). Author? (1994) ISBN 0-901115-81-9
[edit] External links
- The Duke of Gloucester website - more detail and pictures
- Steam Special along the West Cumbria Coast 24th Feb and 10th March 2007
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Britannia Class 7 • Duke of Gloucester • Clan Class 6 • 5MT 4-6-0 • 4MT 4-6-0 • 4MT 2-6-0 • 3MT 2-6-0 |
| Locomotives of GWR • LNER • LMS • Southern |
