dynamometer car

Noun

 * 1)  A piece of railway rolling stock used to measure various aspects of a locomotive's performance.
 * 2) * 1959, Steam's Finest Hour, edited by David P. Morgan, Kalmbach Publishing Co., referring to the Union Pacific "Big Boy" 4-8-8-4:
 * "en"

- Wide open, a 4000 consumed up to 22 tons of coal and 100,000 pounds of water an hour and produced in one authenticated dynamometer-car test 6290 drawbar horsepower at 41.4 miles per hour.