derail position indicator

例句：

1. 1.The train's derail position indicator showed it was about to hit the track.
   火车的脱轨位置指示器显示它即将撞上轨道。
2. 2. The engineer used the derail position indicator to guide the train back onto the tracks.
   工程师使用脱轨位置指示器来引导火车重新回到轨道上。
3. 3. The derail position indicator is crucial for ensuring the safety of railway operations.
   脱轨位置指示器对于确保铁路运营的安全至关重要。