Joe,
I am so sorry to see the damage. I have always been a bit nervous about the shape of the transition from slope to level. However it seemed to work fine. That is until the speed became greater. I suspect that the rails flexed a bit too. Perhaps more cross ties and foundation (or steel reinforcements bolted on) near the transition. Also a camera on each side fixed on the transition might show any potential issues in the future.
Best wishes getting the wheels round and true. (no wobbly Walter please)
Kirk
PS Mike's pole vault students hope for such a launch!