Abstract: The track brake is intended to limit the speed of rolling motion of a freight car according to the track gradient in a marshalling yard. A retarder installed along a braking rail comprises a number of braking tappets each having a portion which projects above the braking rail in the rest position and each being applied in turn beneath each wheel of the car to be braked. The track brake comprises a motion converter constituted by a series of rockers each pivotally mounted on a pin connected to the braking rail. One portion of each rocker cooperates with a braking tappet and another portion of the rocker cooperates with a piston-rod of a substantially horizontal hydraulic brake cylinder.