This power track had problems from the start. It would mysteriously break off wheels. These were tremendously strong, custom-machined super-steel wheels and bearings, yet they would break off, along with other things breaking.
As usual, they would just fix things whenever they noticed something broken, but one day there was a serious breakage. A wheel snapped, and wasn't noticed. Then the other side broke, and a large piece of axle fell into the track. The driver of the train (remotely!) noticed things jamming, and kept going, trying to clear the jam. Finally, the whole thing jammed up and lost power.
We were very lucky that this happened before hot fuel was in the hopper. Had that happened, the cooling water would have boiled off, and there would be a big radioactive mess! Might have even had to go public!
I got brought in because I was a dynamics expert. There was also an outside consultant. I saw the magnificent video of the damage, which would be an instant u-tube hit, if they released it! For at least 10-20 m, the track was totally ripped out, and bent steel everywhere! Better than a Minnesota bridge!
When I saw the broken pieces, I immediately thought of my water laser experience. This was no ordinary fatigue failure, of which I had seen my share (happens all the time!). This was a dynamic break, instantaneous, caused by tremendous force. I told them to get the proper scans, but they never did.
The failures were essentially random. Some pieces were lasting forever, sometimes brand new replacement parts broke. They thickened up some sections on the shaft, then the failures would move to the next area. I saw it as dynamic wave failure, but could not figure out how that could happen.
I went through many more videos, and still pictures of the whole system. I made my little model. The consultant and I agreed that it had to be an alignment problem. Finally, I figured it out. The big frame was flexing dynamically, under certain conditions. Once in a while, a very thick piece of steel on the frame banged against the tracked sled, with explosive force. You could see the impact points on the photos! Dynamic waves went through the sled and popped off wheels, and damaged the cable chain.
We wrote a report, saying how it needed some dynamic monitoring. As well, I wanted some ultrasonic monitoring for bearing damage. I never heard from them again, and I last heard they were still inspecting and fixing things when they broke. A big accident can never, ever happen again......