centre-line of track

例句：

1. 1. The railway is the centre-line of transportation in this region.
   这条铁路是该地区交通的主线。
2. 2.The train tracks are the central line of the railway system.
   火车轨道是铁路系统的主线。
3. 3. The construction of the new highway will be the centre-line of traffic for years to come.
   新建高速公路将成为未来几年交通的主干线。