Dynamometer car, 1949.
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This carriage (no 45049) was built for British Railways (BR) and the London, Midland & Scottish Railway (LMS) in 1949. A dynamometer car enables tests to be made on railway journeys under varying conditions, obtaining information relating to speed, acceleration, superheater and smokebox temperatures. Apparatus contained in the car was activated by an extra wheel which was lowered into contact with the rail when tests were to be made.