The NTSB has completed its investigation into the December 30, 2013 derailment of 20 DOT 111 tank cars near Casselton, North Dakota and determined the cause of the accident to be a broken axle. The incident involved two trains. The train carrying grain was using an axle that had been used on a previous train car. When the axle broke it caused the train to derail. Another train on an adjacent track was carrying crude oil. That train was unable to stop in time and collided with the derailed grain cars.
NTSB issued an urgent safety recommendation to the American Association of Railroads that requires testing to be done on the use of any secondhand axles. In addition, NTSB studied the use of advanced brake systems and additional buffer cars. While the advanced brake system would not have prevented the accident in this case, it may have reduced the amount of damage caused. The crude oil train only had one buffer train between the locomotives and the hazardous cargo. The derailment caused 18 of those 20 cars to spill 476,000 gallons of crude oil. There were no fatalities but the accident and subsequent spill caused almost 1,500 people to be evacuated from their homes.
DOT 111 tank cars have been in the spotlight for several years due to the fact that they are not puncture resistant, there is no thermal protection, they lack top and bottom fittings protection, and are made of relatively thin steel.
The industry has already begun phasing these tank cars out in favor of the DOT 117 tank cars but the official deadline for the discontinued use is not until 2029. The NTSB Chairman, Christopher A. Hart, believes the “progress towards removing or retrofitting DOT 111s has been too slow”.