They are to meet at the station. - Они встретится станцию. They must meet at the station. - Им необходимо встретиться станцию.

First, it would be nice to know whether you are asking about two questions (as you have written them) or whether you really mean the difference between two declarative sentences: 1.They are to meet at the station. 2.They must meet at the station. I will assume you are asking about two declarative sentences. 1. "They are to meet at the station." This means that it is a mutual understanding among the participants (they) that the meeting place is the station. Everyone in the group understands that they will go to the station and meet there. This is perhaps because they have discussed it beforehand and all have agreed that the station is the place where they will meet. This simply states that the participants have decided to meet at the station by agreement. 2. "They must meet at the station." This means that for some reason the participants (they) are compelled to meet at the station. It may be, for example, that all the baggage will be at the station and the group must go there to pick it up. If they do not meet at the station, they will not be able to get their baggage before continuing on their trip. It implies that there is some specific reason why meeting at the station is important, though sometimes the reason is not stated. I hope this helps!

They don't have exactly the same meaning, though they are close They are to meet at the station. = It is planned that they will meet at the station. They must meet at the station. = It is necessary that they meet at the station. The second one implies a negative consequence (or more) if they do not meet at the station.

Oh! I see, my teacher. Thanks a lot:)

Bellow = yell. Below = underneath. Watch the spelling!