The Transportation Safety Board of Canada (TSB) released its investigation report into the main-track train derailment near Sarnia, Ontario.
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On 28 June 2019, a Canadian National Railway Company (CN) freight train was proceeding through the CN Paul M. Tellier Tunnel en route from Sarnia, Ontario to Port Huron, Michigan, United States when a total of 45 cars and one locomotive derailed, including one tank car that released 12 000 U.S. gallons of sulphuric acid.
There were no injuries.
The investigation determined that the accident occurred when a bathtub gondola car sustained a structural failure and the leading end collapsed, resulting in a derailment in the tunnel on the Canadian side of the border.
The car was built in 1978 and was modified in 2012 for use in scrap steel service. At the time of its failure, the car had a number of pre existing defects that contributed to its reduced structural integrity.
Visual examination determined that the defects were not recent but had developed over a period of time.
Despite its deteriorated condition, the car travelled frequently within, and between, Canada and the U.S. and was interchanged between railways 16 times in the six months preceding the accident.
In the three months prior to the accident, it received 24 certified car inspections and had numerous pull-by inspections, with no significant structural defects noted.
Neither the Canadian freight car safety rules, the U.S. freight car safety standards, nor the Association of American Railroads (AAR) Interchange Rules contained limits to identify defects to certain structural components of freight cars, such as those present in the failed gondola car.
Thus, the structural defects did not prevent the car from remaining in service.
Following the derailment, CN inspected 416 of the 2130 identified cars of similar type and vintage to the bathtub gondola car that failed in the tunnel and that were being used in scrap iron and steel service in North America.
CN identified defects in 149 of the 416 cars (36%).
Following this accident, the TSB issued four rail safety advisory letters.ac ■