railway signaling

例句：

1. 1.The train's whistle is used to alert the station staff of its arrival.
   火车的汽笛用来通知车站工作人员火车的到来。
2. 2.The railway signaling system is crucial for ensuring safe travel on the tracks.
   铁路信号系统对于确保轨道上的安全旅行至关重要。
3. 3.The engineer used a railway signaling device to communicate with the driver.
   工程师使用一个铁路信号设备与司机沟通。