​On July 5, 2024, about 3:36 a.m. local time, Canadian Pacific Kansas City Railroad (CPKC) freight train 242-03 derailed 29 railcars, including 17 hazmat tank cars, near Bordulac, North Dakota, as it traveled east on the Carrington Subdivision. Methanol (a flammable hazardous material) was released from some of the derailed tank cars and led to a pool fire. The heat from the pool fire resulted in the release of anhydrous ammonia from other derailed cars. In all, nine hazardous material tank cars were breached (punctured or torn) during or after the derailment and released lading (content of the tank cars). No injuries were reported, but a residence near the accident area was evacuated.​

​We determined that the probable cause of the derailment of Canadian Pacific Kansas City Railroad train 242-03 was the collapse of the subgrade supporting the track structure. 

Contributing to the collapse was an erosion-caused void in the railroad subgrade created by a separation of culvert segments at the accident location, which went undetected because of Canadian Pacific Kansas City Railroad’s insufficient culvert inspection requirements. 

Contributing to the severity of the accident was the release of highly flammable hazardous materials caused by the breaching of five methanol tank cars, which supplied fuel for a pool fire that then led to thermal breaching of three anhydrous ammonia tank cars. 

Contributing to the severity of the release was inadequate thermal performance of the derailed anhydrous ammonia tank cars and the proximity of tank cars transporting highly flammable hazardous materials to tank cars carrying poison inhalation hazard materials in the train consist.

Also contributing to the severity of the release was the continued use of DOT-111 and DOT-117R tank cars, which sustained considerable mechanical damage, and the use of manway gaskets that were vulnerable to thermal damage.​​

​As a result of this investigation, we made the following new safety recommendations.

​To the Pipeline and Hazardous Materials Safety Administration:

• Issue guidance for the selection of an optimal pressure relief device based on the characteristics of the poison inhalation hazard material transported in a tank car. (R-26-1)
• Develop and implement new thermal performance criteria for tank cars carrying liquefied gases classified as poison inhalation hazard materials that allow for no release of the tank car’s lading during a fully engulfing pool fire except through reclosing pressure relief devices. (R-26-2)
• In coordination with the Association of American Railroads, identify the appropriate amount of separation between tank cars transporting poison inhalation hazard materials, including anhydrous ammonia, and those transporting flammable hazardous materials to reduce the likelihood of poison inhalation hazard tank cars being exposed to pool fire conditions. (R-26-3)
• Using the results of the determination described in R-26-3, reduce the vulnerability of tank cars transporting liquefied gases designated as poisonous by inhalation, including anhydrous ammonia, by requiring their physical separation from flammable hazardous materials when placed in a train. (R-26-4)

To the Association of American Railroads:

• Inform your members of the circumstances of this derailment and encourage them to (1) review and revise as necessary their culvert inspection procedures to include a requirement to perform internal inspections either on foot when safe or by using technology, such as cameras or remotely operated vehicles, and (2) provide detailed rating guidance specific to each type of culvert construction, similar to the American Association of State Highway and Transportation Officials’ Culvert & Storm Drain System Inspection Guide as recommended by the American Railway Engineering and Maintenance-of-Way Association, and require remedial actions to be taken within set timeframes, when necessary. (R-26-5) 
• Revise the formula for required pressure relief device flow capacity specified in Appendix A of your Specifications for Tank Cars and the requirements for pressure relief devices and thermal protection systems to ensure the survivability of tank cars carrying poison inhalation hazard materials in engulfing pool fire conditions. (R-26-6)
• ​Support the Pipeline and Hazardous Materials Safety Administration in identifying the appropriate amount of separation between tank cars transporting poison inhalation hazard materials, including anhydrous ammonia, and those transporting flammable hazardous materials to reduce the likelihood of poison inhalation hazard tank cars being exposed to pool fire conditions. (R-26-7)
• Using the results of the determination described in R-26-3, modify train placement instructions contained in your United States Hazardous Materials Instructions for Rail to ensure that tank cars transporting poison inhalation hazard materials, including anhydrous ammonia, are physically separated from flammable hazardous materials. (R-26-8)

To the American Short Line and Regional Railroad Association:​ 

• Inform your members of the circumstances of this derailment and encourage them to (1) review and revise as necessary their culvert inspection procedures to include a requirement to perform internal inspections either on foot when safe or by using technology, such as cameras or remotely operated vehicles and (2) provide detailed rating guidance specific to each type of culvert construction, similar to the American Association of State Highway and Transportation Officials’ Culvert & Storm Drain System Inspection Guide as recommended by the American Railway Engineering and Maintenance-of-Way Association, and require remedial actions to be taken within set timeframes, when necessary. (R-26-9)

​To Canadian Pacific Kansas City Limited:

• ​Revise your culvert inspection procedures to require every culvert be inspected internally, either on foot when safe or by using technology, such as cameras or remotely operated vehicles. (R-26-10)
• Revise your culvert inspection procedures to provide detailed rating guidance specific to each type of culvert construction, similar to the American Association of State Highway and Transportation Officials’ Culvert & Storm Drain System Inspection Guide as recommended by the American Railway Engineering and Maintenance-of-Way Association, and require remedial actions to be taken within set timeframes, when necessary. (R-26-11)