spanning rail

• 对接导轨

spanning rail的用法和样例：

例句

1. Each column is equipped in both planes with a preloaded roller bearing guide rail.
   每个立柱的两个平面均配有预加载滚柱轴承导轨。
2. The welding carriage is adapted to the rails of various diameters,but each rail is adapted to the certain diameter pipe only.
   焊接小车可适应各种直径的导轨，但每一种导轨只能适应一定的管道管径范围。