Skytrain is awesome. Tracks are isolated for some definition of "isolated"; skytrain doesn't have to interoperate with any other rail traffic (unless you count

Skytrain is awesome. Tracks are isolated for some definition of "isolated"; skytrain doesn't have to interoperate with any other rail traffic (unless you count maintenance vehicles) but there isn't any wall separating the track from the station platform like e.g. the Las Vegas airport has (it has been discussed as a safety measure, but skytrains don't presently park accurately enough to line up the doors) and there are many places where you can hop a fence and get onto the tracks (resulting in trains being stopped and police showing up to escort you away).