actually, that was the point of my comment a few parent generations up from linked: by hanging the train under the rail, you get perfect banking for basically free. Fair, entry and exit of turns has to be handled smoothly, but you get passive pendulum-based perfect bank angle at any speed from 0 to the maximum allowed for that radius.
And while it's certainly not cheap to be forced to build the track as "technically a bridge", the lack of serious span makes the cost not actually that bad relative to train track in locations where the curve radius and speeds tend to actually be used (valleys narrow enough to need quite tight radii, as well as near existing infrastructure: if you're already bridging, it's easy to design the pillar point foundations to not conflict with existing usage).
Oh, and about the coffee you mentioned: just like bus and subway, (open) drinks and food are not allowed anyways. In any case, the only substantial forces would be increased gravity, and whatever traction limited acceleration along the direction of travel (this would be with deliberate jerk minimization, though, as people would otherwise loose their footing, where the currently active limits for subways come from).
