On October 15, 2023, about 3:24 p.m. local time, southbound BNSF Railway freight train C-ATMCRD0-31D derailed 31 hopper cars loaded with coal and subsequently killed a nearby driver in Pueblo, Colorado. The hopper cars derailed near a track switch north of a railroad bridge that crosses over Interstate 25. Derailed hopper cars struck and partially collapsed the bridge over the northbound lanes. Six derailed hopper cars fell to the interstate below, with at least one falling on a northbound truck-tractor in combination with a utility trailer, killing the driver. The combination vehicle came to rest beneath the collapsed bridge span, derailed hopper cars, and lading. No members of the train crew were injured.
We determined that the probable cause of the derailment of BNSF Railway train C-ATMCRD0-31D was the train encountering a rail break that occurred when a mismatched thermite weld failed; the thermite weld cracked near the rail’s base because the welder, for unknown reasons, likely did not use a compromise kit during the welding as required by BNSF Railway procedures.