Rail transportation safety investigation R25T0189

Table of contents

    Main-track derailment
    Canadian National Railway Company
    Mile 30.6, Dundas Subdivision
    Paris, Ontario

    The occurrence 

    On 25 July 2025, a Canadian National Railway Company (CN) mixed-merchandise train was travelling west at approximately 30 miles per hour on the north track of the Dundas Subdivision. The train consisted of 172 cars, including 80 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, an uninitiated emergency brake application occurred at Mile 30.6 in the town of Paris, Ontario. A subsequent inspection revealed that 23 cars, including the mid-train locomotive, had derailed upright in two separate sections. 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

    Deployment notice

    TSB deploys a team of investigators following a train derailment in Paris, Ontario

    Photos

    Teams at work following the 25 July 2025, CN train derailment of 23 cars in Paris, Ontario (Source: TSB)

    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

    1. Field phase: a team of investigators examines the occurrence site and wreckage, interviews witnesses and collects pertinent information.
    2. 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.
    3. 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.