It's a time warp, I tell ya or a worm hole. Or, a door into the Matrix, yep that's it, a door into the Matrix. I'll bet if you watch it long enough the guy on the platform will disappear then re-appear.
That also depends on what country it's in. If their steering wheels are on the left side of their cars or on the right side of their cars, that dictates from which direction they board buses and trains.
It depends on which end of the train I look at. If I look at the closest part ... it's moving towards the tunnel. If I look at the part near the tunnel opening, it's coming out of the tunnel.