Do you have the idea of switch and crossing?

Here is the answer : Switch and crossing, a kind of line connection equipment turning the rolling stock from one line to another one, is usually laid massy at the station or the marshal-ling yard. With the assistance of switch and crossing, the passing capacity of lines can be greatly improved.

Unclear? Please look at the sketch map:

Working Map of Switch and crossing

Next let us enjoy the following esthetical love story:

He and She

A pair of good friends

Two parallel lines

Extend on the road of their each life

He and she

Having thought there would be no interaction for them

Become lovers

Living naturally and unrestrictiedly in the world of mortals

Sharing the prosperous social lives and pentium forward

But

Turnout, the naughty guy

Break up The parallel lovers

Let true lovers fall in deeper love

Let false lovers part company

......

Got it? That is turnout, one reasonable thinker doing the job of separation and reunion.