Rail transportation safety investigation R24D0080

This is the summary of a class 5 occurrence to which TSB investigators deployed. The investigation is now closed. Updated on 17 January 2025.

Table of contents

    Train derailment
    Canadian National Railway Company (CN)
    Mile 69, St-Hyacinthe Subdivision
    Longueuil, Quebec

    The occurrence

    On 14 November 2024, Canadian National Railway Company (CN) freight train M32231-13 (the train) was travelling eastward on the south service track of Southwark Yard in Longueuil, Quebec, near Mile 69 of CN’s St-Hyacinthe Subdivision. It consisted of 102 cars: 60 loaded cars, 33 empty cars, and 9 residue cars. It weighed 9156 tons and was 6242 feet long.

    At approximately 0827, after the train had switched over to track A075 and was travelling at about 9 mph, a train-initiated emergency brake application occurred.Once the train came to a stop, the crew inspected it and found that 8 cars had derailed. The last 2 derailed cars fouled a service track and the south main track (Figure 1).

    Figure 1. Partial view of the derailment site, including the cars fouling the tracks (Source: TSB)
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    Figure 1. Partial view of the derailment site, including the cars fouling the tracks (Source: TSB)

    No other cars derailed, and no injuries were reported. Two of the derailed cars were tank cars containing dangerous goods. The first tank car was loaded with propane (UN1075) but did not leak. The second car was loaded with hydrogen peroxide (UN2014). It remained upright, but its side wall was punctured, resulting in the partial release of its contents.

    A team of investigators from the Transportation Safety Board of Canada (TSB) was deployed to the site on the day of the occurrence and in the following days to collect data and assess the situation.

    Initial response

    An emergency call was made to the 9-1-1 call centre at approximately 0845. Between 0855 and 0910,

    Figure 2. Initial safety perimeter put in place around the derailment site (Source: ArcGIS, with TSB annotations)
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    Figure 2. Initial safety perimeter put in place around the derailment site (Source: ArcGIS, with TSB annotations)

    Transport Canada remedial measures specialists arrived around 1100. These specialists play several roles on accident sites involving dangerous goods, including ensuring the safety of the public and staff on site, assessing the efficiency and safety of the remedial measures taken, and making recommendations to the incident commander when necessary.

    Following the assessment of the release of dangerous goods situation, it was decided to establish a lockdown within the safety perimeter. Longueuil’s municipal services initiated the broadcasting of automated messages at approximately 1155 to notify the residents located within this perimeter.

    Various emergency response teams, including a CN dangerous goods officer, also arrived on site with their respective specialized material. After assessing the condition of the derailed rolling stock, an action plan, which included the transfer of the dangerous goods in the two tank cars, was developed and implemented.

    A specialized team responded to ensure the proper transfer of dangerous goods. The transfer of hydrogen peroxide that was left in one of the derailed tank cars was completed at approximately 0300 on 15 November, and the transfer of propane from the other derailed tank car was completed at approximately 1630 on 16 November.

    The lockdown, the perimeter of which had been gradually reduced during the day, was lifted at approximately 0400 on 15 November.

    Site examination by TSB investigators

    A total of about 373 feet of railway track was destroyed. A section of damaged rail from the start of the derailment area was recovered and examined by the TSB (Figure 3).

    Figure 3. Profile view of the two corresponding parts of the cracked rail (Source: TSB)
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    Figure 3. Profile view of the two corresponding parts of the cracked rail (Source: TSB)

    This section came from a 100-pound rail that had sustained a head-web separation, because of an internal rail defect related to metal fatigue. Progression of this type of defect can occur very rapidly with repeated heavy traffic.

    The rail had 10 mm of wear on the running surface and 6 mm of wear on the gauge side, for a combined wear of 16 mm. This level of combined wear exceeds the maximum level of 14 mm prescribed by CN’s Engineering Track Standards to keep 100-pound rail in service.

    The upper portion of the rail head also showed significant deformation (creep) toward the field side of the rail. This kind of deformation usually occurs when a section of rail has been subjected to heavy loads for many years (Figure 4).

    Figure 4. Wear and deformation on a cracked rail (Source: TSB)
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    Figure 4. Wear and deformation on a cracked rail (Source: TSB)

    It was not possible to determine with certainty either the year of manufacture or the manufacturing process used for the recovered rail.

    According to information gathered by the TSB, the most recent ultrasonic testing of the rails in the vicinity of the derailment was carried out on 22 November 2023 to identify possible internal defects.

    Conclusion and safety communication

    Following the assessment of the occurrence on site and the examination of the recovered parts, TSB investigators found safety deficiencies and identified remedial measures that can reduce safety risks.

    On 19 December 2024, the TSB issued Rail Transportation Safety Advisory Letter 06/24 to Transport Canada on inspection requirements of tracks such as those located in rail yards to ensure that they remain fit for continued service. This advisory provides the regulator, who has the ability to make the required changes, with relevant information and TSB investigators’ findings. As a result, this puts an end to the TSB’s investigation activities related to this occurrence.

    Safety Communications

    2024-12-19

    Rail Transportation Safety Advisory Letter 06/24

    Investigation information

    Map showing the location of the occurrence

    R24D0080

    Train derailment
    Canadian National Railway Company (CN)
    Mile 69, St-Hyacinthe Subdivision
    Longueuil, Quebec

      Download high-resolution photos from the TSB Flickr page.

    Class of investigation

    This is a class 5 investigation. Class 5 investigations are limited to collecting data, which are then stored in the modal database. If TSB investigators deployed to the occurrence site, a short description of the occurrence is posted to the TSB website once the investigation has been completed. These investigations are generally completed within 90 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.