File:Hudswell Clarke D810 Enterprise at Ashford Steam Centre 1972 (8613530103).jpg

Hudswell Clarke D810

What appears to be a standard Hudswell Clarke 0-6-0 diesel mechanical shunter is in fact a unique and highly unusual prototype demonstrator, NºD810 built in 1958, Enterprise. Though the bodywork is standard, the engine is anything but; it was a normally-aspirated Paxman 6RPH fitted with a Brown Boveri turbocharger and extensively modified to work on Paxman's "Hi-Dyne" system intended to produce maximum power output and torque at low speed - which was more achievable with expensive hydraulic or electric transmission rather than cheaper mechanical transmissions. The transmission fitted to D810 was an experimental "Fluidrive" mechanical transmission. Unfortunately, the modifications resulted in a reduction in power of the standard normally aspirated engine from 275 hp to 210 hp, which negated many of the advantages of the Hi-Dyne principle. The loco worked at various collieries and steel works. The only orders which followed was for 24 2'6" gauge 2-8-2 mixed traffic locomotives (even though the Hi-Dyne principle was specifically designed for shunters!) for the Sierra Leone Government Railways built in 1957-61. The locomotives proved highly unreliable despite many modifications and the Hi-Dyne principle was shown to be a failure. D810 is pictured in "as withdrawn" condition, at the Ashford Steam Centre, 10/1972, the last time it's existence is recorded.

UPDATE - the loco was scrapped in Booth's scrapyard, Rotherham in early 1992. But what was it doing and where in the intervening 20 years? Scanned photograph taken with a Kowa SET.