That's because it's a fable. Legend has it an low clearance/overhang knocked the camera off. But think about it, just how many low clearances do you recall on Racer?
The actual truth is, the train returned and the camera mount had failed. The camera was still in place, but had fallen to the side.
Saying it was "knocked off and could have killed a Brady" sounds much more dramatic. When in fact, they still used the same camera for the on-ride filming.
The more difficult piece of that shot was how the cast had to remain "staggered" in their seats. Jan and Bobby had to sit far apart. Behind them, Mrs Brady and Alice had to sit closer together. Finally, Marcia and Greg had to crouch down and close together to be seen. Pay attention the next time you watch it.
Neither Cindy or Mr Brady (Robert Reed) would ride it. In actuality, Robert Reed refused just because he was typically a bitter, stubborn, obstinate man.
Shaggy
Thanks for clearing that up, I guess the Dippin Dots guy got interviewed by Nick when they made this.
And I watched again for the seating on The Racer, I never noticed that either, they all are staggered.