Workers continue to clean up remaining tank cars, Tuesday, Feb. 21, 2023, in East Palestine, Ohio, following the Feb. 3 Norfolk Southern freight train derailment.
Matt Freed | AP
Federal authorities on Thursday pointed to an overheated wheel bearing on a Norfolk Southern train that derailed and released toxic chemicals earlier this month in Ohio.
The preliminary report from the National Transportation Safety Board did not offer an exact cause of the East Palestine, Ohio, derailment but outlined several operational concerns.
“Surveillance video from a local residence showed what appeared to be a wheel bearing in the final stage of overheat failure moments before the derailment,” the report said. “The wheel bearing and affected wheelset have been collected as evidence and will be examined by the NTSB.”
Future investigative activity will focus on the wheelset and bearing, tank car design and maintenance procedures, derailment damage, inspection practices and a review of the accident response.
At about 9 p.m. local time on Feb. 3, an eastbound Norfolk Southern freight train derailed, including 11 tank cars carrying hazardous materials that subsequently ignited. These chemicals included vinyl chloride, a highly flammable carcinogen. Thirty-eight railcars derailed in the incident, according to the NTSB report.
According to the report, the train was traveling about 47 miles per hour at the time of the derailment, below the speed limit of 50 miles per hour. The train’s positive train control system, in place to prevent over-speed derailments, was operating at the time of the derailment.
After the train passed a wayside defect detector, it transmitted an alarm message instructing the crew to stop the train to inspect the hot axle. The Norfolk Southern train was equipped with a hot bearing detector system, designed to detect overheated bearings.
At the time the train was instructed to stop, the bearing’s temperature recorded a temperature of 253 degrees hotter than ambient temperatures, above a threshold of 200 degrees at which point temperatures are considered critical, according Norfolk Southern criteria. At the previous detector, it recorded a temperature of 103 degrees above ambient temperatures.
A one-mile evacuation zone was implemented after the derailment, impacting up to 2,000 residents.
Two days after the derailment, temperatures continued to rise within five of the derailed tank cars carrying 115,580 gallons of vinyl chloride. Due to the possibility of a catastrophic explosion that could have sent shrapnel up to a mile, Norfolk Southern carried out a controlled release three days later.
No fatalities or injuries were reported.
The Thursday report comes the same day that Transportation Secretary Pete Buttigieg visited the site.
National Transportation Safety Board Chairwoman Jennifer Homendy and Director of the NTSB’s Office of Railroad, Pipeline and Hazardous Materials Robert J. Hall will hold a press conference Thursday afternoon at the agency’s Washington, D.C. headquarters.
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