Hangar One is gigantic, and like another commenter mentioned, you get weather patterns, and it's spacious enough to fly inside. Unfortunately the ground is tainted by a lot of heavy metals and the like. If I recall, there was consideration to scrap it, but public outcry is what saved it.
The wikipedia article on it has more. It doesn't have a monorail, but a twin set of narrow-gauge tracks that run along that was for a mooring mast that guided the airships in and out.
Anyways, let's get down to what's important: Reg units!
The doors were not hydraulic, but electric, with 110 kW (Hey Reg! We need units for power!) motors to slide open the 42.86 kiloJub doors.
Measuring 37.5 double-decker busses long and 10.2 double-decker busses wide, it weighs in at 1.6 microwales, meaning you could have 8 football pitches (6 full American football fields) in it. It stands 6.5 double-decker busses high and dwarfs nearby water towers.
Lately, the panels have been removed, leaving just the truss structure that was underneath. It's always strange driving by it on 101, because it looks like reality's video card hiccuped and decided to draw Hangar One as a wireframe.