Question

why is cross in back of train

Answer 1

they remind we people that there is danger

Answer 2

It is a symbol to mark the end of train , also it can be shown that the wagon is the last one , a train without this symbol can be understood that there are some missing wagons . There are other functions of it , but I know this much only.

Hey Smart guy, hope I was helpful, If yes , please mark this as brainliest.