The Turbomotive was a modified Princess Royal Class steam locomotive designed by William Stanier and built by the London, Midland and Scottish Railway in 1935. It used turbines instead of cylinders. It was later rebuilt as a conventional locomotive 46202 Princess Anne.
This was one of the few experimental steam turbine locomotives which really did beat conventional engines on thermal efficiency, despite having no condenser. The main reason for its high thermal efficiency was that it had six separate steam nozzles and they were controlled individually as on or off and not throttled. It 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. These were war years of extra heavy demands and little tolerance of waste. It was taken out of turbine service due to a failed forward turbine, and the turbine was not repaired because Stanier was no longer in charge in the nationalized system.
The forward turbine had 18 rows of blading. Output was 2400 hp at 7060 rpm, corresponding to running at 62 mph. Boiler pressure was 250 lbf/in² (1.7 MPa). The turbine was designed to operate into a maximum back-pressure of 2 lbf/in² (14 kPa), 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.
The reverse turbine had 4 rows of blades. It was engaged by the dog-clutch mechanism. This was originally steam-operated by a small piston and cylinder.
46202 Princess Anne
46202 was rebuilt as a conventional locomotive in 1952 and named Princess Anne. After only two months in service it was involved in the Harrow and Wealdstone railway accident. It was the train engine of the double headed Liverpool and Manchester express which ran into the wreckage of the first collision which had happened seconds before. The locomotive was removed to Crewe works but was later deemed to be damaged beyond economical repair and subsequently scrapped.
London, Midland and Scottish Railway locomotives
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