The only parts on Raptor that are rusting are the rails, and that's because B&M didn't want the rails painted for some reason. All the B&M rides are like that, except for some newer ones that are painted. Don't know why the change in policy on those rides. Just by looking at the rails, the rust only appears to by light surface rust. It should be many, many years before they need to be replaced. An interesting thing about Millennium Force is that the rails are painted, except where the wheels contact the rails. This seems like a great solution and would probably work on Raptor and Mantis also.