The fundamental problem in the establishment and solution to the spatial vibration equation of train-track (bridge) time-varying system at home and abroad is analyzed in detail.

分析了国内外在列车-轨道（桥梁）时变系统空间振动方程的建立及其求解过程中存在的根本问题。

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He would fall over the bridge onto the track right in the way of the trolley car.

他就会摔下桥,正好摔在电车轨道上挡住电车。

耶鲁公开课 - 公正课程节选

You're standing on a bridge overlooking a trolley car track.

你站在一座桥上，俯瞰着电车轨道。

耶鲁公开课 - 公正课程节选

As we cross the snaking, single-track bridge there is a glimpse of Loch Shiel, and of the monument that marks the spot where Bonnie Prince Charlie first assembled his Jacobite army that nearly did so well for the Scots.

BBC: Full steam ahead

The first stage of work is focused on increasing train speeds on 23 miles (37km) of track between Norton Bridge and Crewe from 75mph to 100mph.

BBC: Work on Staffordshire rail 'bottleneck' begins

The steep track on the other side of the bridge looks even worse, cut by even deeper gullies.

BBC: Diary of an aid worker