This is probably a stupid idea, but I think it would be cool if you took a suspended coaster's train and track, added wheels, and ran it on bobsled coaster track, it would make a different ride. You could literally fly off of every turn, and it would be a little scary to see the track dissapear in the middle of a helix.
It wouldn't be much different than a regular bobsled except for floorless trains...
That would probably cause a lot of friction.
