By Steve Wishnia

The February 2023 derailment of a freight train in East Palestine, Ohio, that forced the evacuation of more than 2,000 people was caused when an overheated wheel bearing on a hopper car caused the axle to separate, the National Transportation Safety Board said in a summary of its forthcoming report released June 25.

The railroad’s trackside “hot box detectors,” the board said, failed to show just how hot the bearing had gotten. It said the safety regulations covering them are weak or nonexistent. It also concluded that the Norfolk Southern Railway’s decision to release toxic vinyl chloride gas from tank cars in a “vent and burn” three days later was “not necessary” to prevent an explosion.

The 149-car train, bound from Madison, Illinois, to a railyard near Pittsburgh, derailed when the left front journal on the 23rd car, the connection between the wheel and the axle, “burnt off,” NTSB investigator Joey Rhine told a board meeting in East Palestine. The cylinder containing the bearings for the axle had melted to a conical shape, he said.

Another investigator, Greg Scott, said that the detector in Salem, Ohio, 20 miles west of East Palestine, had sent out a “not critical” alarm when it found the journal 103 degrees hotter than the air temperature. That number “did not reflect the true temperature,” he said, because the inside of the cylinder was likely hotter. By the time the train reached the East Palestine detector, its sensor found the bearing 253 degrees hotter, the maximum it could show. It sent out a “critical alarm—hot box” that required the train to stop.

Security-camera footage from along the tracks showed a fire under the car several miles before it reached East Palestine. Several cars caught fire after they derailed.

“The combination of Norfolk Southern Railway standard operating procedures that required only continued monitoring for non-critical bearing alerts,” the NTSB summary said, “the limited ability of hot bearing detectors to measure a bearing’s actual internal temperature, and the distance between detectors did not give the train’s crew adequate warning to stop the train before the suspect bearing failed and caused the derailment.”

The board found that the train crew’s handling and response did not contribute to the derailment.

Lack of regulations

The Federal Railway Administration has no regulations for responding to hot-box alarms, Scott said. After the East Palestine crash, the Association of American Railroads [AAR], the trade group that represents the six major freight carriers, lowered the temperature at which trains are supposed to stop and be inspected from 200°F to 170°F. 

But, Scott said, no action is required on non-critical alerts until after they have been received from three consecutive detectors, and they are monitored remotely. The train crew was not notified.

A non-critical alert, veteran engineer Hugh Sawyer told Work-Bites earlier this year, means “it’s not serious, but it’s going to be serious.” He said the East Palestine disaster “definitely could have been prevented.”

About 25% of the cars on the train had “federal defective conditions,” Rhine said. The bearings in the car that failed had all been reconditioned—something he’d seen in two other accidents he’d investigated recently.

The Fire And Gas Release

Thirty-eight cars derailed, including at least eight that carried hazardous materials. Three tank cars carrying inflammable materials were breached, and a fire ignited. The fire reached four of the five tank cars carrying compressed liquified vinyl chloride gas, a toxic and inflammable chemical used in manufacturing plastics.

Three days later, fearing that the vinyl chloride would polymerize—individual molecules combining into a chain, which can generate enough heat to cause an explosion—the commander at the scene ordered a “vent and burn,” releasing gas from the cars for 70 minutes and setting it on fire.

Norfolk Southern employees on the scene assumed polymerization was imminent, NTSB hazardous-materials inspector Paul Stancil told the meeting. But representatives from Oxy Vinyls, the manufacturer, said there was a low probability of polymerization. The temperatures in the tank cars were dropping instead of heating up, investigators said. Polymerization is a “standard reaction,” but it typically starts with an external initiator such as high temperatures, a retired Stony Brook University chemistry professor told Work-Bites.

However, Oxy Vinyls had no contact with the incident commander, Stancil said, and Norfolk Southern showed a “pattern of dismissing contradictory evidence.” The commander was “not aware of dissenting opinions,” the NTSB said.

Norfolk Southern defended its decision in a statement, saying it was “the only option to protect the community from a potential catastrophic explosion,” and that Oxy Vinyls representatives could have talked to the incident commander themselves.

NTSB chair Jennifer Homendy reacted angrily at the end of the meeting, saying that Norfolk Southern had refused to turn over information the board had requested or claimed it didn’t exist, and that it tried to submit its own investigation four times.

The train also was not covered by federal regulations for “high hazard” trains, Stancil said, because only two cars were categorized as high-hazard. The federal minimum is 35 cars on a train or 20 cars in a consecutive block. Association of American Railroads standards set a 50-mph speed limit for “key trains” with 20 such cars, bringing it down to 30 mph when there’s a hot-bearing alert—but the East Palestine train had only 17 such cars.

Recommendations

The NTSB will release its final report later this summer. Its preliminary recommendations include:

• Railroads must immediately give emergency responders information about the identity and location of toxic materials on a train in the event of an accident.

• Establishing minimum requirements for wayside bearing detectors.

• Requiring that placards listing toxic cargo be able to remain legible after fires and accidents.

• Updating manufacturers’ information on vinyl-chloride hazards, especially about when polymerization is a risk.

• Speeding up the phaseout of DOT-111 tank cars, a 30,000-gallon model that is the most common tank car in use. They are supposed to be replaced by cars meeting the federal DOT-117 standards by 2029. The fires in East Palestine, the NTSB said, likely started because hazardous materials had been released from a punctured DOT-111 car.

The NTSB has been warning about safety problems with DOT-111 cars for more than 30 years, and increased its standards for strength in 2011. They were involved in a five-day chemical fire in Baltimore in 2001 and the oil-train fire and explosion in Lac-Mégantic, Quebec in 2013, which killed 47 people.