You can see all the verbs in the past simple in black and bold: applied, opened, switched, and so on.

应用、打开、转变，等等。

A spontaneous switchman, one who opens switches as and when he pleases without regard to orders from those above him who know better, would be a menace to the traveling public.

一个自发的扳道工，一个随心所欲地打开开关的人，而不考虑他更了解的上级的命令，这将对旅行的公众构成威胁。