News from the Financial Associated Press, February 24 (Editor Zhao Hao)On Thursday (February 23), local time, the National Transportation Safety Board (NTSB) released a preliminary report on the derailment of the East Palestine train in Ohio.
accident cause
At approximately 20:54 pm on February 3, Norfolk Southern Company general merchandise freight train “32N” derailed on the No. 1 main track in East Palestine, Ohio, the report said. The accident derailed 38 carriages, including 11 tankers carrying hazardous materials.
The tank cars caught fire after they derailed, causing a fire and damaging 12 other cars that did not derail. After the incident, emergency personnel implemented an evacuation zone with a radius of 1 mile around the derailment site, and as many as 2,000 residents were affected.
According to the report, the 32N train includes 2 locomotives and 149 carriages, and there is a distributed power system between 109 and 110 carriages. Among them, 20 sections are tank trucks marked with hazardous materials, and the transported goods include flammable liquids, flammable liquids and flammable gases.
Norfolk Southern is understood to have equipped its rail network with an axle temperature monitoring system. At the time of the incident, the system issued an alarm to the train personnel. According to data, the temperature difference between the bearing and the environment may reach as high as 253 degrees Fahrenheit.
After the train came to a stop, crews noticed fire and smoke in the carriages and immediately notified dispatchers of a possible derailment. The 32N train was traveling at approximately 47 mph (75 km/h) when it derailed, well below the 50 mph (80 km/h) speed limit.
release vinyl chloride
Emergency crews moderated the fire on Feb. 5, but five DOT-105 derailed tank cars carrying 115,580 gallons of vinyl chloride continued to be a concern, with temperatures still rising inside one of the cars. The rising temperature indicated that the vinyl chloride was polymerizing and could cause an explosion, the report said.
Emergency crews arranged for “controlled ventilation” of five vinyl chloride tank trucks to release and burn the vinyl chloride and expanded the evacuation zone to a 2-mile radius.
The release process started at around 16:40 pm on February 6 and lasted for several hours. Emergency crews also dug trenches to contain the release of vinyl chloride as the liquid vinyl chloride evaporated and burned.
follow-up investigation
The National Transportation Safety Board inspected railroad equipment and track conditions at the scene, reviewed signaling systems and detectors, collected local surveillance camera and train interior records, and conducted interviews with relevant personnel.
The committee concluded that the first car to derail was the 23rd car. Surveillance video also showed that a wheel bearing in the carriage was suspected to have overheated failure. The wheel bearings and affected wheel sets have been collected as evidence for inspection by the NTSB.
Some analysts believe that the mechanical failure of the wheel bearings has exposed the serious defects of the old American freight railway infrastructure and insufficient operation and maintenance capabilities, which is also the most important reason for the derailment of the “poisonous train”.
NTSB emphasized that the agency’s future investigation activities will focus on wheel sets, bearings, tank car design, and review of the response measures to burn vinyl chloride. The NTSB is not involved in investigating air monitoring, water quality testing, environmental remediation and evacuation orders, and questions should be referred to the Environmental Protection Agency.