The LMS Turbomotive 6202


Updated: 15 Aug 2014

Smokebox drawing added
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Left: The LMS turbine locomotive, No 6202, built in 1936.

This locomotive looks fairly conventional but was in fact driven by a steam turbine ahead of the coupled driving wheels. It was non-condensing, and had a reversing turbine, engaged for use with a dog-clutch.

This was one of the few experimental turbines which really did beat conventional engines on thermal efficiency, despite having no condenser. This has to be called an engineering success; it covered over 300,000 miles between 1936 and 1945, and was finally taken out of turbine service in 1949. It was rebuilt as a conventional Pacific, and was eventually written off in the catastrophic accident at Harrow in 1952.

Above: Two more views of 6202, showing its clean lines compared with a piston locomotive.

Above: removing the turbine casing.

Right: One end of the forward turbine. The curved pipes run from the six control valves down to the turbine nozzles.

Above: Side elevation drawing of Turbomotive 6202.
Source: "Locomotives", by A M Bell. 1946

Above: a very rare cutaway drawing of the business end of Turbomotive. Note the six valves controlling the forward turbine inlet nozzles.
Source: the "Popular Science Educator", date unknown.

Above: Side elevation, showing forward (main) turbine.

Above: Plan of front end. The forward turbine is at the bottom of this drawing.

Above: Cross-section of the forward turbine, with 18 rows of blading. Output was 2400 hp at 7060 rpm, corresponding to running at 62 mph. Boiler pressure was 250 lb/sqin. The turbine was designed to operate into a maximum back-pressure of 2 lb/sqin, allowing a conventional double blast-pipe to provide the boiler draught, and eliminating draught fans, which always seemed to give a disproportionate amount of trouble.

Left: Cross-section of the 4-row reverse turbine, showing the dog-clutch mechanism. This was originally steam-operated by the cylinder at lower right in the drawing.

Above: Inside of the smokebox of Turbomotive, showing twin blastpipes


R Tufnell "Prototype Locomotives" pub David & Charles, 1985. ISBN 0-7153-83973
Charles Fryer "Experiments With Steam" pub Patrick Stephens, 1990. ISBN 1-85260-269-4
A M Bell "Locomotives" 5th Edn, Virtue & Co, 1946.
O S Nock "The British Steam Railway Locomotive 1925-1965" Ian Allan 1966

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