The Psychoaster said:
Does centripetal force hold the trains straight on the suspended corkscrews? Because otherwise I can't think how it wouldn't just flop over to one side as it went inverted - considering it is allowed to freely swing?
That's the idea, hence the really tight corkscrew. Despite this, it still didn't work. They just couldn't get the control they needed over the swinging cars to ensure it would negotiate the element properly every time.
It's probably a good thing in some ways that they never tried it on a real coaster. Imagine if the train came to a halt halfway through the corkscrew, there'd be cars dangling in all sorts of directions.