Some people are so like eternal pointsmen lying in wait by the line, to shunt one's train of thought from one rail to another.
有些人就像永远守候在线路旁的指挥官,将一个人的思路从一条轨道转移到另一条轨道。
英语百科
Switchman
A switchman (North America) or pointsman (British Isles) is a rail transport worker whose original job was to operate various railway switches or points on a railroad. It also refers to a person who assists in moving cars in a railway yard or terminal or one who operates the switches of mine tracks in a coal mine.