I doubt Site-19 would have a full blown underground railway, a tram system like in Black Mesa or the London underground would be fine, but something like what you pictured, far too excessive.
Speaking of the underground:
I like this station design.
I'm just hoping this kind of thing is possible, it's a common theme in containment breach for rooms to be built around the map algorithm, for example, the maintenance tunnels, big circle leading back to where you started, the doors you enter and exit through are only around 10 meters apart..
I'm not here as much right now, mention me on our Discord server if you need anything.