I think it all comes to a human fact . There was only one guy aboard , he parked his trains around 11 at night , pitch black outside . The guy was probably tired of his run .
The other team was supposed to arrive shortly . He let the loco running like he did many times before .
He probably did not feel to walk in the dark to set up hand brakes on 12 or 14 cars ( about a 1,000 feet walk each way ) .
After setting up the hand brakes he was supposed to come back in the loco to try to pull the train , if the locos can still move the train he is supposed to walk another 1,000 feet back and forth to set up more hand brakes .
I am not trying to excuse the guy , not at all , it's a combination of many factors that cause that tragedy .
No matter what the train was carrying , a paper or wood train would have cause quite a mess , for sure .