Abstract: A yaw damper for railway cars comprises a pair of rotary hydraulic units connected to the laterally extending truck bolster of a railway truck assembly on opposite sides of its central pivot bearing member, a pair of connecting plates secured to the corresponding laterally extending car body bolster under a railway car in position on the truck assembly on opposite sides of the corresponding pivot bearing member of the car body bolster, the rotary hydraulic units on the truck bolster connected to respective ones of the connecting plates on the car body bolster by respective ones of a pair of longitudinally adjustable connecting rods. The connecting rods are connected at one end to the pivotable crank or stabilizing lever of respective ones of the hydraulic units and at the other end to connecting lugs of respective ones of the connecting plates.