Train Derailments

How Trains Derail, Explained by an NTSB Investigator  WSJ

Northern Southern Derailment

  • After the Ohio Train Derailment: Evacuations, Toxic Chemicals and Water Worries NYT
    • Around 9 p.m. on Feb. 3, a train derailed in East Palestine, a village of about 4,700 residents about 50 miles northwest of Pittsburgh. There were 150 cars on the route from Madison, Ill., to Conway, Pa. The National Transportation Safety Board said that 38 cars derailed and a fire ensued, damaging another 12 cars.
    • The train, operated by Norfolk Southern, had been carrying chemicals and combustible materials, with vinyl chloride, a toxic flammable gas, being of most concern to investigators.
    • On Feb. 6, the authorities released the toxic materials from five tankers, and the contents were diverted to a trench and burned off.


Truck / Bogie


Axle Roller Bearing

Hot Box Detector

  • From: Here’s the most thorough explanation yet for the train derailment in East Palestine (NPR)  and NTSB Preliminary Report (
    • Train 32N comprised 2 head-end locomotives, 149 railcars, and 1 distributed power locomotive located between railcars 109 and 110. 
    • 38 railcars derailed, including 11 tank cars carrying hazardous materials that ignited. The train was going 47 mph, under the 50 mph speed limit.
    • Train 32N passed three HBD systems on its trip before the derailment.
      • At MP 79.9 the bearing from the 23rd car recorded a temperature of 38°F above ambient temperature of 10 degrees F.
      • At MP 69.01, 11 miles later, the bearing had reached 103 degrees
      • At MP 49.81, 19 miles later just east of East Palestine the temperature of the bearing was 253°F triggering an alarm instructing the crew to stop the train to inspect a hot axle.
    • Norfolk Southern safety guidelines require train operators:
      • to stop and inspect wheel bearings between 170 and 200 degrees Fahrenheit
      • to stop and remove the affected car from the train if the temperature is above 200 degrees Fahrenheit
  • There are about 3 U.S. train derailments per day. They aren’t usually major disasters NPR
    • There were at least 1,164 train derailments across the country last year, according to data from the Federal Railroad Administration.
    • Human error was the leading cause of derailments in 2022, with track defects being the second-most-common cause.
  • Rail Heat Sensors, Under Scrutiny in Ohio Crash, Face Few Regulations NYT
    • Some safety experts said that if Norfolk Southern had more detectors closer together near East Palestine, the train crew might have had more time to avert disaster.
    • Federal railway regulators last week identified two other Norfolk Southern derailments last year that appeared to involve overheated bearings. 
    • The federal government does not require the use of temperature detectors along tracks, nor does it regulate how such equipment is inspected or maintained. Those decisions are left up to railroads and their trade association.
  • N.T.S.B. Will Investigate Norfolk Southern’s Safety Practices NYT
    • The National Transportation Safety Board said on Tuesday that it had opened a special investigation into safety practices at Norfolk Southern because the company had suffered five significant accidents since December 2021, including a major derailment in East Palestine, Ohio, last month.