(CNSNews.com) – The National Transportation Safety Board says its investigation of the Feb. 3 Norfolk Southern freight train derailment in East Palestine, Ohio is “ongoing,” but it released a preliminary report today.
The investigation is focusing on a wheel bearing and wheelset that overheated in the 23rd car of the 149-car train; the tank car design and derailment damage; a review of the accident response, including the venting and burning of the vinyl chloride; railcar design and maintenance procedures and practices; the use of wayside defect detectors; and railcar inspection practices.
The report said 38 train cars went off the tracks, including 11 tank cars carrying hazardous materials that subsequently ignited, setting an additional 12 non-derailed cars on fire.
The train was traveling about 47 mph at the time of the derailment, which was less than the “maximum authorized timetable speed of 50 mph.” The positive train control system was enabled and operating at the time of the derailment.
The train had a dynamic brake application that was operating when it passed a “wayside defect detector” east of East Palestine. The defect — a hot bearing — sounded an alarm, telling the crew “to slow and stop the train to inspect a hot axle.”
The train engineer decelerated; an automatic emergency brake kicked in; “and train 32N came to a stop.”
The report says the train passed three places on the Fort Wayne Line where overheated bearings could be detected:
— At milepost 79.9, the suspect bearing from the 23rd car had a recorded temperature of 38°F above ambient temperature (which was around 10 degrees Fahrenheit).
— At milepost 69.01, the bearing’s recorded temperature was 103°F above ambient.
— And at milepost 49.81, the bearing’s recorded temperature was 253°F above ambient.
“After the train stopped, the crew observed fire and smoke and notified the Cleveland East dispatcher of a possible derailment,” NTSB said.
“With dispatcher authorization, the crew applied handbrakes to the two railcars at the head of the train, uncoupled the head-end locomotives, and moved the locomotives about 1 mile from the uncoupled railcars. Responders arrived at the derailment site and began response efforts.”
Two days after the derailment, with temperatures still rising inside five of the derailed cars carrying vinyl chloride, emergency responders scheduled a controlled venting to release and burn the vinyl chloride.
“They expanded the evacuation zone to a 1-mile by 2-mile area, and dug ditches to contain released vinyl chloride liquid while it vaporized and burned. The controlled venting began about 4:40 p.m. on February 6 and continued for several hours.”
The NTSB has recovered the apparently defective wheel bearing anad wheelset as evidence. The vinyl chloride tank car top fittings, including the relief valves, were also removed and examined by the NTSB.
NTSB continues to work with the investigative parties to determine what exactly caused the derailment and to evaluate the emergency response efforts.
The NTSB says it is not involved in air monitoring, testing of water quality, environmental remediation, or evacuation orders.
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