https://youtu.be/-WqrvUlOYis
Word is the coal train suffered a mid train derailment/leaning equipment which a passing train struck. Caused lead unit to uncouple and roll onto single track and bumped head-on into another train. Loco brake cylinders were sheared off in the side swipe which made independent brakes fail.
Crew apparently bailed when impact was imminent. All low speed but major weight on big trains.