train approaching sensor

例句：

1. 1. The train will arrive at the station in 30 minutes.
   火车将在30分钟后到达车站。
2. 2. He took a train to visit his grandparents in another city.
   他乘火车去另一个城市的爷爷奶奶家。
3. 3. She decided to take a train to work instead of driving her car.
   她决定乘火车去上班，而不是开车。