Are you here yet?

1-3 are fine. I'd probably use a version of 2.

4 sounds a little odd, though not wrong, because you'd expect to see the person if they were "here".

I also might say: "Where are you now?" or "What's your ETA?" (Estimated Time of Arrival)

tinanam0102If you are meeting someone at at an ATM outside a mall, and they haven't arrived yet. You call them to check on their location. How would you say it?

To check on their location, which is essentially finding out where they are, I would say, "Where are you?"

"Are you here yet?" and the others like that will not tell you their location, becaus

Hi CalifJim, hi vorpar,

Thanks for your help.

1. If you're on a subway train, someone calls you and asks you where are you? If the train stops in B going to C and your destination is G. Would you say, I'm in B?

2. If you're to meet someone on the platform of the subway, When the train pulls into the station and eventually stops, there are two ends, would you say,

tinanam0102If you're on a subway train, someone calls you and asks you where are you?

"I'm on the train. We just passed the X stop."

tinanam0102would you say, meet me at the front of the train to G?

I don't think "to G" has anything to do with it.

"Meet me at the front of the train."

CJ

CalifJimI don't think "to G" has anything to do with it.

In my country, the platform, where the train stops, is divided into so-called sectors: A, B, C, D, E, F, G. So it is wise to ask the train conductor at which part of the platform the passenger carriage which one is in is going to stop.

Hi CalifJim, hi anonymous,

Thanks for the help.
TN

Hi CalifJim,

I'm sorry I may have written it wrong. When you say 'at the front of the train', do you mean physically 'inside the train'? My description of the scene is we meet on the platform (one end where the train operator is), and then we wait for the train to come and get on it. (In Hong Kong we have two opposite tracks where the plateform is in between them.)

Thanks

tinanam0102When you say 'at the front of the train', do you mean physically 'inside the train'?

No. I mean on the platform where the front of the train is located when it's ready for you to get on.

CJ

Hi CalifJim,

Thanks for the explanation. Would it be also understandable:

Let's meet at the end of the (platform) train.
Let's meet in the middle of the (platform) train.

Thanks
TN

tinanam0102Let's meet at the end of the (platform) train. Let's meet in the middle of the (platform) train.

Those are not as understandable as they could be. Not if you say them exactly like that. Say one of these:

Let's meet [at the end / in the middle / at the front] of the train.
Let's meet on the platform [at the end / in the middl