The investigation is going to have to check the rails and the cars. A single burned bearing can be enough to initiate a derailment. The bearing can go from "Ok" to burned off in the space of 3 minutes time. There is insufficient information to draw any conclusions at this point.
Talk about spooky....
Driving to work this morning, I hoped in the car, started it up, checked the clock and it was 9:11.
Doing a restore this evening, the process called tape 911.
That's it. I'm going home and hiding under the bed. LOL!