NTSB says CN track repair left curve unsafe before Mississippi derailment
Article Summary
Source-basedOn 13 October 2026 the National Transportation Safety Board (NTSB) released a final investigation report into the Glendora derailment that occurred on 5 July 2025 on Canadian National’s (CN) Yazoo Subdivision in Mississippi. The report attributes the derailment of a southbound mixed freight train to wheel climb caused by a deformed stretch of a curve that had not been properly repaired after a CN track maintenance operation. CN’s own automated inspection vehicle had identified superelevation defects on the curve on 2 July 2025, and a surfacing crew tamped part of the curve the following day. However, the crew’s limited work, driven by heat‑related concerns, left the curve in a less stable condition than before, creating a mismatch that ultimately led to the derailment. CN subsequently imposed speed restrictions and conducted further inspections, but the NTSB found that the track remained unstable. The investigation also uncovered gaps in CN’s record‑keeping and a history of recurring defects linked to unstable Yazoo clay subgrade. CN has since undertaken corrective actions, including a rail‑destressing program and repairs on similar curves. The NTSB’s findings highlight deficiencies in project management and record maintenance that allowed a known safety concern to persist until the accident.
The report underscores the importance of rigorous track geometry monitoring, especially on curves with a documented history of instability. It also illustrates the potential consequences of inadequate repair practices and incomplete documentation in the rail industry. CN’s response includes additional inspections and a commitment to meet continuous welded rail plan requirements, reflecting a broader industry push toward improved safety oversight and maintenance standards.
RailZoom Intelligence Brief
Original synthesisLead
On 13 October 2026 the National Transportation Safety Board (NTSB) issued its final investigation report on the Glendora derailment that occurred on 5 July 2025 on Canadian National’s (CN) Yazoo Subdivision in Mississippi. The incident forced the evacuation of approximately 160 residents and involved the derailment of 22 cars, including a benzene‑laden tank car that caught fire. No injuries were reported.
Verified facts
The NTSB determined the probable cause to be wheel climb triggered by a deformed stretch of the curve between mileposts 97.5 and 97.7. CN’s automated track inspection vehicle had identified two superelevation defects on 2 July 2025, and a surfacing crew tamped part of the curve the next day. The crew reported working between 435 and 600 feet of a curve that is roughly 1,785 feet long, but no post‑work measurement confirmed restoration of geometry. CN imposed a 10 mph speed limit for the next two trains, then raised it to 30 mph; video of the first two trains showed the anomaly still present and growing. The accident train passed at 29.1 mph, below the limit.
CN’s own damage assessment placed the cost at approximately $1.5 million. The NTSB found gaps in CN’s records for the curve, including missing or inaccurate entries on rail plug installations, rail temperatures during adjustments, and rail additions or removals. Over time the track drifted toward the inside of the curve and off its engineered subgrade.
Organizations and responsibilities
Canadian National (CN) – responsible for track maintenance, inspection, and record‑keeping on the Yazoo Subdivision. CN’s automated inspection vehicle identified defects; a surfacing crew performed tamping; CN senior management has implemented corrective actions and a rail‑destressing program.
National Transportation Safety Board (NTSB) – conducted the investigation, determined probable cause, and issued the final report.
Federal Railroad Administration (FRA) – inspected the CN line between Memphis and Greenwood during the week of 21 July 2025, recording 206 defects, 147 linked to CN’s FRA‑approved continuous welded rail plan.
Operational and commercial context
The NTSB’s findings highlight the risks associated with limited repair work on curves with a history of instability, especially when performed in hot weather. The report notes that CN’s approach to tamping was “normal in hot weather” but less effective on a curve with documented instability. The mismatch created by the partial tamping increased the likelihood of wheel climb, leading to the derailment.
CN’s subsequent actions—speed restrictions, additional inspections, and a rail‑destressing program—reflect an industry trend toward stricter adherence to continuous welded rail plans and improved track geometry monitoring. The investigation also underscores the importance of comprehensive record‑keeping for tracking rail neutral temperature and stress, which was lacking in this case.
Sources
https://www.railway.supply/ntsb-says-cn-track-repair-left-curve-unsafe-before-mississippi-derailment/ – Railway Supply
Disclosure
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