A screwing machine tightens or releases rail fixing screws. The screwing machine contains a machine frame which can be rolled on a track, handles for moving the screwing machine, a motor for applying a torque to a screw head, and a device for transmitting a torque. A measuring device is provided opposite the machine frame in order to detect a reaction torque of the motor. The motor is actuated in order to limit the torque depending on the reaction torque. The reaction torque is used as a reference variable. The reaction torque is applied to the machine frame by the motor and is ascertainable with a high degree of precision by a simple measuring device. In this manner, a simple and robust design and a precise rotational speed limiting function are implemented.