by An overheated wheel bearing was involved in a freight train derailment in East Palestine, Ohio, U.S. government investigators say
technology
February 23, 2023
Cleanup efforts continue in East Palestine, Ohio after a train carrying chemicals derailed Tannen Maury/EPA-EFE/Shutterstock
The eastern Ohio freight train derailment involved a faulty wheel bearing that overheats without first triggering the alert threshold set for the railroad’s fault detectors, according to a preliminary report by federal safety investigators.
The Norfolk Southern Railway train passed three roadside detectors before the derailment, which led to a spill of toxic chemicals from several wagons. Two of the three detectors registered the rising temperatures of the overheated wheel bearing, but only the third detector, in East Palestine, Ohio, registered a temperature high enough to trigger an alert to train crew. Norfolk Southern has not yet publicly responded to the report’s findings.
“Norfolk Southern should revise its sounding criteria to include the rate of temperature rise between measurements,” said Russell Quimby, a retired US National Transportation Safety Board investigator.
Within the privatized US railroad system, railroad companies set their own temperature thresholds for the trackside detectors, also known as hot-box detectors. The US Federal Railroad Administration, which creates and enforces US rail safety regulations, does not currently set standards for such detectors.
“Surprisingly, they are not mandated or regulated in any way,” says Jared Cassity, director of the transportation division at the International Association of Sheet Metal, Air, Rail, and Transportation Workers.
Cassity also expressed concern that the first two track detectors registered a 36 °C (65 °F) rise in temperature without any warning or information being sent to train crews.
Only the third detector, near the site of the derailment in eastern Palestine, sent an alert to train crews after measuring a temperature more than 122°C above ambient.
Norfolk Southern typically requires train conductors to stop and inspect warm wheel bearings when their temperatures are between 76 and 93 °C (170 and 200 °F). Railcars with wheel bearing temperatures above this should be separated from the train and discarded.
“This one appears to have driven about 30 miles before it failed, which was ample time for the car to be parked in a siding,” says Quimby. “Camps that rise in temperature as much as this don’t typically get cooler.”
After receiving the detector’s warning, the train engineer increased the application of the dynamic braking system, which uses the train’s engines as generators to slow the train and dissipate mechanical energy as heat. An automatic braking system also activated the train’s main air brakes – something that can be deployed if a derailment severed the air brake hose between the railcars.
The freight train was traveling at about 47 miles per hour (76 kilometers per hour) at the time of the derailment.
“As an industry, railroads will use this initial report to develop a thoughtful, fact-based approach to preventing another similar accident before it can happen elsewhere,” the Association for American Railroads, an industry organization, said in a prepared statement.
However, train workers’ unions have raised safety concerns about the major US rail freight companies, which have implemented precisely planned railroad strategies that pressure crews to perform train inspections more quickly. Cassity describes that inspection times for rail vehicles have decreased from 3 to 4 minutes per car to around 30 to 60 seconds per car.
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