NS 16N Freight Train Derailing - Cresson, PA

Today, 12/27/14, I planned a trip up onto the west slope of the Pittsburgh Line and meet up with Jordan and Brett. While waiting for Jordan (NS6321_40E) to show up, 16N pulls up and stops due to issues with its leader (NS 6309). When the train stopped, the headend stopped pulling but the Helper Crew on the helpers kept pushing, causing the train to serge. Finally, with the problems fixed in the leader. (I am not saying that was the cause of the derailment, nor am I placing the blame on them, I am talking ab