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Dynamometric (Test) Car
(rail dynamometric car), a device for traction testing of motor vehicles, tractors, locomotives, and the like. A dynamometric car is towed at various speeds by the equipment being tested, and the effort transmitted through a coupling device is measured (the draw-bar pull). The force constitutes the difference between the tractive force developed by the test object and the resistance to its movement.
In order to carry out tests at various speeds and to discover the full draw-bar pull of the object being tested, the resistance to movement of the dynamometric car (given constant profile and surface of the right-of-way) is artificially changed using a braking device mounted on it and connected to its wheels. Tests can also be carried out under different road conditions (different profile and surface of the right-of-way). The draw-bar pull of the object tested is measured by a dynamometer. Dynamometric cars can have one, two, or several axles.