Hollowed out Control Tower glass insides, by request.

Fixed strange building corners. Unfortunately, this adds triangles to the map, and so performance suffers some.

I also added a control station to the shed near the roundhouse, where you can control the Far Z Clip Plane of the map. This allows you to choose performance or visuals on the fly. The lower the number, the better performance you get.

Added an extra siding near the railyard, as well as another crossover.

Major optimization pass. Should give 3x better FPS minimum, and surpasses that in some areas.