The train consisted of 72 “DOT-111″ tanker cars, which have been criticized in the past to “have a high incidence of tank failures during accidents” (NTSB report report, page 75). … The energy for that breaking action is supplied by a air pressure reservoir on each car. … Even if the magnitude of the incident at Lac-Megantic is unusual, air brakes failing and insufficient hand brake force resulting in run-away equipment and a subsequent collision is not unusual. This is