It happened to a new coaster (Superman at SFA) twice in its first couple of weeks... the first time while I was on it!
I don't know how often parks replace chains, but I think Cedar Point generally replaces theirs at least every two or three seasons, necessary or not. Given the length of Magnum's chain, I'm surprised it doesn't happen more often. It's been several years since it happened last... perhaps someone can remember which year?
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Jeff
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