They're actually rail tracks, and #4 is on the overpass
Just kidding I have no idea what's going on there
Ok, at first I thought you were right, but I looked at it and I figured it out. The stairs are going down, not up, therefore you are crossing on the level of the tracks. So the line that is blocking on both sides of the tracks is a gate.
Oh that makes sense, but I think its an underpass below the tracks, you can kind of see the dots marking underpass blending in with the surrounding walls.
oh yeah, that makes sense