California roller coaster shut after brain damage claims. LOS ANGELES: A popular California roller coaster is being permanently shut down after dozens of people claimed to have suffered brain damage while riding it. The X2 at Six Flags Magic Mountain features precipitous drops and jarring twists that have thrilled millions of riders over two decades, with seats that swivel 360 degrees as cars travel at speeds of up to 80 miles (130 kilometers) an hour.