Concerning Dynamic Brakes and this incident. It is important to understand that, assuming these are 3 modern AC locomotives, each equipped with Extended Range Dynamic Brake, they should be capable of generating around 115,000 - 120,000 Lbs. of retarding effort apiece. Total of all 3, under the best of adhesion conditions, would be somewhere in the neighborhood of 340,000 to 360,000 lbs. Dynamic Brake retarding effort (in their most effective speed range of 6-23 mph).
A 112 car loaded grain train would weigh somewhere around 14,500 -15,000 TONS (30 million lbs.). Bottom line is that this consist would not have been capable of maintaining any speed descending this type of grade using Dynamic Brakes alone. It would be necessary to supplement the Dynamic Brake with an air brake application in order to keep the retarding forces sufficient to control the train at the desired speed. Blending an air brake application along with the locomotive Dynamic Braking effort would be absolutely necessary to slow or stop the train on this heavy of a downhill grade.
Severe sub-zero (F) temperatures can do strange things to the air brake train line.
Employee statements from all active participants, (crew, any local managers, and control station), any recordings from radio conversations, position of the controls on the controlling locomotive, event recorder downloads (from all 3 locomotives) and post accident mechanical inspection of the equipment, should provide all the information needed to understand what events occurred resulting in this accident.
The $64 question is "What will be done to prevent it from re-occurring?"
