A freight train derailment in eastern Ohio involved a failed tire that overheated without initially triggering the alert threshold set for rail defects, according to a preliminary report by federal safety officials. investigator
The Norfolk Southern Railway train passed three wayside detectors before the derailment which led to a toxic chemical spill from several train cars. Two of the three detectors recorded an increase in the temperature of the overheating wheel bearing, but only the third detector in East Palestine, Ohio, recorded a temperature high enough to trigger a warning to the train crew.
“Norfolk Southern needs to reevaluate their shipping practices to include the rate of temperature increase between readings,” said Russell Quimby, a retired investigator for the US National Transportation Safety Board.
Within the private US freight rail system, freight railroad companies set their own temperature thresholds for wayside detectors, also known as hot box detectors. The US Federal Railroad Administration, which creates and enforces US railroad safety regulations, does not currently set standards for such detectors.
“Surprisingly, they are not required, nor regulated in any capacity,” said Jared Cassity, director of the transportation division of the International Association of Sheet Metal, Air, Rail, and Transportation Workers.
Cassity also expressed concern about the fact that the temperature rose to 65°F (36°C) between the first and second wayside detectors but no warning or information was sent to the train crew.
Only a third detector located near the East Palestine derailment site sent a warning to train crews after recording a temperature greater than 253°F (122°C) above ambient temperature.
Norfolk Southern typically requires train crews to stop and inspect hot tire tracks when their temperature is between 170 and 200°F (76-93°C). Rails with tire bearing temperatures beyond the standard should be separated from the train and placed on the rail sidings branching from the main track.
“This one seemed to go about 30 miles before it failed, with plenty of time to put the car on a siding,” Quimby said. “Bearings rise in temperature as gradually as this one is not usually cooler.”
After getting the detector’s warning, the train engineer added the use of a dynamic braking system that uses the train’s motors as generators to slow the train and dissipate the mechanical energy as heat. An automatic braking system also activates the train’s main air brakes – something that can be triggered if a derailment disconnects 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.
Norfolk Southern said in a statement that its trackside detectors triggered a temperature “among the lowest in the railroad industry.” It also said that all wayside detectors at the scene of the incident were found to be operating as designed.
“As an industry, railroads will use this initial report to shape a thoughtful, fact-driven approach to prevent another similar accident before it happens elsewhere,” said the Association for American Railroads. , an industry organization, in a prepared statement.
But railroad unions have expressed safety concerns over major U.S. freight railroad companies implementing precisely scheduled rail strategies that force crews to perform train inspections. which is faster. Cassity described train inspection times as reduced from 3 to 4 minutes per car to about 30 to 60 seconds per car.
The tire that failed was on a rail with many plastic pellets, said Jennifer Homendy, chair of the National Transportation Safety Board, in a press briefing on February 23. The hot axle connected to the wheel bearing together with the plastic pellets to start the initial fire accompanied by derailment.
Such tires can fail for a variety of reasons, including fatigue cracking, water or mechanical damage, a loose bearing or a tire defect. Federal investigators are still looking into possible causes.
“The roller bearings failed,” said Homendy. “But it’s absolutely critical for problems to be identified and addressed early so they don’t run to failure.”
The investigation did not uncover any operational issues with the roadside detectors. But Homendy said federal investigators will look into how Norfolk Southern used and set up trackside detectors, along with how train crews received alerts from the detectors.
He also highlighted the wide variety of detector standards among railroad companies and the lack of federal regulation for detectors. “The warning threshold is set by the railroads, and it varies by railroad,” Homendy said. “We’ll see if we need to change.”
Before issuing a final report, the National Transportation Safety Board plans to hold an “unusual” investigative field hearing in East Palestine this spring. That process includes talking to the public, gathering facts from witnesses, and discussing and agreeing on possible solutions.
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