Wood coasters squeak for similar but different reasons than steel. Most wood coaster trains can't steer like steel trains. As a result, the turns need to be lubed so the trains can slide around turns. When the rails are lubed, you get the metal-on-metal grinding and squeaking that Mean Streak and more recently Beast and Sonny are known for.
Steel coaster trains can steer around turns so generally no lube is needed. Then why does MF squeak around the turn? There's probably a little resistance going on between the wheel and rail. The nylon wheels are different enough from standard polyurathane wheels that they make a squeaking sound when there's drag.
How can they fix it? I've got two ideas. One, put a little lube on the track. Since MF is running fast enough, I don't see this happening. The second idea came about when from Rideman sometime last year when the new wheels came in. Split each wheel down the middle so effectively you have two wheels in one. As a result, the wheel can turn at two different speeds, one for the inside and one for the outside of the turn. It's this difference in rotation speeds that causes the squeak. Allow for different rotation speeds and the squeaking should go away as well as resistance between the rail and wheel that could very well yield a faster ride.
Yes, it's a slow day at work :)
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Scott W. Short
scott@midwestcoastercentral.com http://www.midwestcoastercentral.com