normally energized track circuit

例句：

1. 1. The engineers designed the normally energized track circuit to ensure safe operation of the train system.
   工程师设计了通常被能量化的轨道电路，以确保火车系统的安全可靠运行。
2. 2. The new security system uses a normally energized track circuit to prevent unauthorized access.
   新的安全系统使用了通常被能量化的轨道电路来防止未经授权的进入。
3. 3.The power grid is equipped with normally energized track circuits to monitor and control power flow.
   电力网配备了通常被能量化的轨道电路来监控和控制电力流动。