[外语] 这句英语翻译是对是错？

这个翻译是对的，will和be going to是差不多的，但be going to常用在已经计划好了，基本上一定会发生的事；will可以用在想表达意愿的时候。

USE 3 "Be going to" to Express a Plan
"Be going to" expresses that something is a plan. It expresses the idea that a person intends to do something in the future. It does not matter whether the plan is realistic or not.

Examples:

He is going to spend his vacation in Hawaii.
She is not going to spend her vacation in Hawaii.
A: When are we going to meet each other tonight?
B: We are going to meet at 6 PM.
I'm going to be an actor when I grow up.
Michelle is going to begin medical school next year.
They are going to drive all the way to Alaska.
Who are you going to invite to the party?
A: Who is going to make John's birthday cake?
B: Sue is going to make John's birthday cake.

另外，我想‘他们正在去地铁站’是不是可以这样说：They are on the way to the station. 觉得不妥敬请指出。.