It's the train you came in on. After a few minutes it pulls its doors shut, continuing on the path laid out for it. If you want to go home, you'd have to get to the other side of the east-west platform, but in order to do that you'd need to go down the elevator and then walk over there and then go back up, and you're not sure why you'd just turn around after coming all this way. You might as well find somewhere to rest now that you've gotten here.