hind quarter rail dropper

例句：

1. 1. The rear quarter rail of the crane is essential for lifting heavy loads.
   起重机的后部四分之一轨道对于起重重物至关重要。
2. 2. The rear quarter rail of the car was damaged in the collision.
   汽车的后部四分之一轨道在碰撞中受损。
3. 3. The rear quarter rail of the bridge supports the weight of the roadbed.
   桥梁的后部四分之一轨道支撑着路基的重量。