EAST PALESTINE, Ohio — The National Transportation Safety Board released a preliminary, 4-page report of their investigation on the train derailment in East Palestine, Ohio on Thursday, 20 days after several train cars filled with hazardous materials derailed and caught fire.
The report seems to corroborate the NTSB's initial suspicions that a mechanical issue with a rail car axle is possibly to blame for the derailment. In it, NTSB says the train passed three different hot bearing detectors, the third of which transmitted a critical alarm message to the train's crew to stop the train to examine a hot axle; the train's engineer initiated the train's dynamic brakes to slow and stop the train, the report says.
"During this deceleration, an automatic emergency brake application initiated," and the train came to a stop, the report says. It was then that crew members saw fire and smoke and called dispatchers to report a possible derailment, NTSB says.
The three hot bearing detectors passed by the train recorded one of the axle's temperature as it increased dramatically in the miles between the sensors. At mile marker 79.9, NTSB said the bearing from the train's 23rd car was recorded at 30 degrees Fahrenheit above ambient temperature. Around 10 miles later, at mile marker 69.01, the bearing's temperature was 103 degrees above ambient temperature. When the car passed mile 49.81, the bearing was 253 degrees above ambient temperature, which triggered the system's alarm.
NTSB said Norfolk Southern's alarms are triggered if:
- Temperatures are detected between 170 degrees and 200 degrees, a non-critical alarm instructs crews to stop and inspect the bearing
- A difference between bearings on the same axle is recorded at 115 degrees or higher, crews are notified to stop and inspect
- Temperatures are greater than 200 degrees, a critical alarm instructs the crew to stop the train and "set out" the railcar for repairs
According to the report, at around 8:54 p.m. on Feb. 3, 38 cars derailed on the eastbound Norfolk Southern train, including 11 tank cars carrying hazardous materials "that subsequently ignited, fueling fires that damaged an additional 12 non-derailed railcars."
First responders evacuated roughly 2,000 residents from the 1-mile radius around the derailment site; there were no reported injuries or deaths, NTSB said.
"At the time of the accident, visibility conditions were dark and clear; the weather was 10 degrees Fahrenheit with no precipitation," reads the report.
The train was comprised of two head-end locomotives, 149 railcars and one distributed power locomotive positioned between cars 109 and 110, according to the report. Twenty of the cars were labeled as carrying hazardous and containing combustible liquids, flammable liquids and flammable gas, including vinyl chloride.
According to the report, the train was traveling around 47 mph at the time of the derailment, less than the maximum allowed speed of 50 mph.
After the derailment, first responders at the scene found five derailed DOT-105 cars — a pressurized tank car often used to carry hazardous materials. These cars, railcars 28 through 31 and car 55 were carrying 115,580 gallons of vinyl chloride and one tank was increasing in temperature, NTSB says.
"This increase in temperature suggested that the vinyl chloride was undergoing a polymerization reaction, which could pose an explosion hazard," the report says.
The evacuation zone was increased to a 1-mile by 2-mile area and responders dug ditches to contain the released chemicals while a "controlled venting of the five vinyl chloride tank cars" could be performed.
On Feb. 6 at around 4:40 p.m., the controlled venting began and continued for several hours, NTSB says.
The report stops short of saying for certain whether the overheated wheel bearing was the cause of the derailment; it acknowledges that 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 says further investigation will focus on the wheelset and bearing, tank car design and derailment damage, a review of the accident response including the venting and burning of vinyl chloride, railcar design and maintenance procedures and practices, Norfolk Southern's use of wayside defect detectors and Norfolk Southern's railcar inspection processes.
That wheel bearing and the affected wheelset have been collected as evidence, NTSB says, and will be examined. The vinyl chloride tank car top fittings, including the relief valves, were also removed and examined by NTSB on scene, the report says. The top fittings will be shipped to Texas for testing, NTSB says.
The hazardous material tank cars have been decontaminated and the investigation is ongoing, NTSB said.
You can read the full report below:
RRD23MR005 East Palestine OH Prelim by WCPO 9 News on Scribd