逆轉機
逆轉機是動力鐵路車輛上用於設定行駛方向，通常位於駕駛室內透過操縱桿進行操作的控制裝置。除了前進、倒退，類似變速箱，也有用於使傳動系統脫離動力的空檔。
Vehicles equipped with a reverser can run both forward and backward with equal capacity, and are even equipped with lights on both ends for this purpose. Depending on the vehicle design, the only difference when changing orientation can be the driving visibility, and cooling behavior.
Reversers should never be operated when vehicles are in motion, to avoid catastrophic damage to the powertrain. For the same reason, to operate the reverser, throttle and dynamic brakes need to be disengaged.
Many vehicles only have one set of controls, facing a particular direction. To drive these vehicles in the opposite direction comfortably, it helps to use the universal control stand, or a locomotive remote controller, if supported.