Because it usually takes a long time to sit by train, during such a long time, a person is lonely and bored. Actually, I really hope others can talk to me.
So don't be afraid to say something, just ask, hey, where is the girl going, and then she will answer you where you are going, so you can ask her if she is going to travel or go home. If she is going home and the destination is still the same, then you are a great fate. You can tell her where your home is, and maybe you are still fellow villagers.
If she is a tourist, then she is a girl who likes to go out to play. You can tell her about your own travel experience. It would be perfect if you knew where she had been. At this time, you can also ask for a contact information so that she can contact you when she doesn't know, and you can go out to play together in the future.
And if she is traveling, you can also ask her why she goes out to play by herself and why her boyfriend doesn't accompany her. Through this conversation, you can know whether she has a boyfriend.