Maximum track irregularity is the evaluate index in emergency maintenance and standard deviation of section track irregularity is the evaluate index in track maintenance machine work.

轨道不平顺最大值用于紧急补修评价指标，区段的标准差用于大型养路机作业的评价指标。

youdao

The author suggests a new system to do track maintenance and repair work separately on Datong-Qinhuangdao Railway Line.

建议大秦铁路线路养护维修工作试行养修分离新体制。

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Buses began using the route in August while another company was brought in to complete work on the maintenance track.

BBC: Guided bus wheel