Knott’s Accident Confounds Experts

As Knott’s Berry Farm prepared to install metal safety devices today on its wooden GhostRider roller coaster, industry experts remained perplexed over the Monday accident that injured five people on the ride.

Wooden roller coasters have proven designs with tremendous safety records over decades of use, said Michael M. Black, chief executive of Roller Coaster Corp. of America in Atlanta, a leading manufacturer of wooden coasters.

“They just very seldom have problems,” Black said. “I’ve heard of people running trains together and things like that, but they just don’t come apart.”

That’s what makes the Knott’s accident, in which a 3-foot shard of wood broke loose beneath GhostRider’s cars and struck five riders, so confounding to the experts, he said.

Wooden roller coasters are held together with an enormous number of 5/8-inch and 3/8-inch bolts, typically used every 3 feet.

“For a board to just come off, I don’t understand it,” Black said. “I can’t imagine a piece of wood coming off a laminated track. . . . It doesn’t make sense.”

GhostRider’s designer, Denise Dinn-Larrick of Custom Coasters Inc., was not available for comment Wednesday. After examining the Knott’s ride Tuesday, Dinn-Larrick returned to her company headquarter near Cincinnati, where she approved Knott’s plans to install metal bracing straps and ribbed nails in the stacks of wood beneath the coaster.

Black said his company, a Custom Coasters competitor, has no plans to make safety modifications on the wooden coasters it has built because it believes the accident at Knott’s was a freak event.

Ray Rieger, a spokesman for the Assn. of Amusement Ride Safety Officials, said that because wooden roller coasters have built-in flexibility to handle the trains’ weight, their bolts often break, unknown to passengers.

He supports pending legislation in California that would regulate the industry and require inspections and reporting of accidents.

“Wooden roller coasters are built to sway and move. Things can easily come apart,” said Rieger, whose group sets design standards for theme park rides.

However, the pieces of wood held together by the bolts usually don’t fly off, Rieger said.