Main-track derailment
Canadian National Railway Company
Mile 30.66, Dundas Subdivision
Paris, Ontario
The occurrence
On 25 July 2025, a Canadian National Railway Company (CN) mixed-merchandise freight train was travelling west on the north main track of the Dundas Subdivision. The train consisted of 172 cars, including 81 equipped with end-of-car cushioning devices, and was powered by three head-end locomotives and one distributed power locomotive positioned mid-train.
At 0510 Eastern Daylight Time, while the train was travelling at about 0.8 mph, a train-initiated emergency brake application occurred at Mile 30.6 in the town of Paris, Ontario. A subsequent inspection revealed that the mid-train locomotive as well 23 cars in two distinct blocks had derailed upright. Two of the derailed cars were carrying hydrochloric acid; neither was breached.
The rails and track were significantly damaged. No injuries were reported. The TSB is investigating.
Media materials
Photos
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Class of investigation
This is a class 4 investigation. These investigations are limited in scope, and while the final reports may contain limited analysis, they do not contain findings or recommendations. Class 4 investigations are generally completed within 220 days. For more information, see the Policy on Occurrence Classification.
TSB investigation process
There are 3 phases to a TSB investigation
- Field phase: a team of investigators examines the occurrence site and wreckage, interviews witnesses and collects pertinent information.
- Examination and analysis phase: the TSB reviews pertinent records, tests components of the wreckage in the lab, determines the sequence of events and identifies safety deficiencies. When safety deficiencies are suspected or confirmed, the TSB advises the appropriate authority without waiting until publication of the final report.
- Report phase: a confidential draft report is approved by the Board and sent to persons and corporations who are directly concerned by the report. They then have the opportunity to dispute or correct information they believe to be incorrect. The Board considers all representations before approving the final report, which is subsequently released to the public.
For more information, see our Investigation process page.
The TSB is an independent agency that investigates air, marine, pipeline, and rail transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.