​On July 6, 2025, about 3:19 p.m. local time, southbound Canadian National Railway train A48871-06 derailed 21 mixed-freight railcars on the Grenada Railroad, a Pinsly Railroad Company subsidiary, near Sardis, Mississippi. The derailed equipment included four tank cars carrying hazardous materials: two containing sulfuric acid and two containing sodium hydroxide. One of these tank cars (a DOT-111 tank car) breached, releasing about 10,500 gallons of sodium hydroxide. Canadian National Railway and Grenada Railroad estimated damages to be about $2 million. No injuries were reported. Visibility conditions at the time of the derailment were partly cloudy with no precipitation; the temperature was 93°F.

We determined that the probable cause of the July 6, 2025, train derailment in Sardis, Mississippi, was Grenada Railroad’s inadequate repair of a track buckle that occurred 10 days before the derailment at the same location, which resulted in the track buckling again under the accident train.

Contributing to the severity of the derailment was a manufacturing defect in a coupler shank on the lead end of the 45th railcar, which caused the coupler shank to break, removing mechanical support for the trailing railcars.​

​The Sardis derailment demonstrates the importance of proper track-repair practices, particularly the need to promptly destress CWR in response to tight-rail conditions, including track buckles. By destressing rail that exhibits tight-rail conditions, railroads treat the underlying cause of track buckles rather than the symptoms. Railroads should remain vigilant to the dangers of track buckles even if CWR represents only a small percentage of their total-rail trackage.