effective length of station track

例句：

1. 1. The effective length of the tunnel is 50 meters.
   隧道的有效长度为50米。
2. 2. The effective length of the road is 10 kilometers.
   道路的有效长度为10公里。
3. 3. The effective length of the bridge is 80 meters.
   桥梁的有效长度为80米。