I believe it would work, however there would be as much friction as an outward angle...let me explain. If the rollercoaster had a 92 degree drop, the friction would be the same as a rollercoaster with an 88 degree drop. A 90 degree drop would be frictionless (in theory). However, the greater frictional force would be on the upstop wheel instead of the wheels on top.
Of course, all of this is my theory, remember, all of this is in an ideal environment, I'm not taking into account wind resistance or weight per se.
But wouldn't the coaster cars come into effect here: the weight of most rollercoaster cars is down near the track (except for those Morgan trains:), the non-Phantoms Revenge ones that is). Wouldn't a coaster car need to be redesigned so that the weights would be up higher? Otherwise, wouldn't it put a tremendous amount of strain on the track and chassis of the car? The stuff about the cars is what I'm not as sure about. Oh, I don't know...I give up! Someone give me a hand here:)!
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A New World. A New Technology. One Last Hope for Salvation. Neon Genesis Evangelion
*** This post was edited by Coastercraver on 6/16/2001. ***