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Here I want to focus on the technical matters of train operation, defect detection, the accident (derailment), which is currently under investigation (by NTSB and FRA) and the investigation itself.
https://www.ntsb.gov/investigations/Pages/RRD23MR005.aspx
The derailment became significant when tank cars of vinyl chloride released the flammable contents and caught fire. One of the tank cars heated to the point where an exothermic polymerization reaction was apparent and an explosion anticipated, which precipitated a 'controlled' release into the environment, and burning of the vinyl chloride, which produced HCl and phosgene in the air. Other freight cars, some carrying plastic, also caught fire.
Preliminary report - https://www.ntsb.gov/investigations/Documents/RRD23MR005 East Palestine OH Prelim.pdf
Summary:
So 38 cars derailed starting with the 23rd freight car through the 60th car (and may be the 61st as well). Five derailed DOT-105 specification tank cars (railcars 28–31 and 55) carrying 115,580 gallons of vinyl chloride (about 23,116 gal per tank car)
NTSB/FRA will have to look at these restrictions in light of an axle that failed catastrophically before the train was stopped. Tank car design will probably be considered as well.
A posted video shows sparks from the wheels (IIRC, the lead truck/bogie) of the 23rd car, a covered hopper car. One narration claimed the video was taken about 20 miles before the derailment, which would put the video near the HBD detector at MP 69.01. I don't know if that is true.
More details will come as information is verified.HBD = Hot Box Dectector (old term) or Hot Bearing Detector (modern term). Hot box originated when freight car trucks had journal (friction) bearings and the boxes formed in the cast steel frame held lubricant. Modern freight trucks (wheel sets) use sealed roller-bearings. I used to help my grandfather oil/lubricate journal bearings on freight cars back during the 1960s, before such equipment was phased out for roller bearings.
Maps care of USA Today
https://www.usatoday.com/story/grap...railment-ohio-explained-graphics/11251530002/
For those interested in Code of Federal Regulations on tank cars
https://www.govinfo.gov/content/pkg/CFR-2012-title49-vol3/xml/CFR-2012-title49-vol3-part179.xml
Some vinyl chloride tank cars may carry nearly 26k gallons.
https://www.gbrx.com/railcars/25800-gallon-vcm-pressure-tank-car/
https://www.ntsb.gov/investigations/Pages/RRD23MR005.aspx
The derailment became significant when tank cars of vinyl chloride released the flammable contents and caught fire. One of the tank cars heated to the point where an exothermic polymerization reaction was apparent and an explosion anticipated, which precipitated a 'controlled' release into the environment, and burning of the vinyl chloride, which produced HCl and phosgene in the air. Other freight cars, some carrying plastic, also caught fire.
Preliminary report - https://www.ntsb.gov/investigations/Documents/RRD23MR005 East Palestine OH Prelim.pdf
Summary:
I expect the report will eventually indicate the mile post (MP) at which the derailment occurred. It happened east of the town.On February 3, 2023, about 8:54 p.m. local time, eastbound Norfolk Southern Railway (NS) general merchandise freight train 32N derailed 38 railcars on main track 1 of the NS Fort Wayne Line of the Keystone Division in East Palestine, Ohio. (See figure.) The derailed equipment included 11 tank cars carrying hazardous materials that subsequently ignited, fueling fires that damaged an additional 12 non-derailed railcars. First responders implemented a 1-mile evacuation zone surrounding the derailment site that affected up to 2,000 residents. There were no reported fatalities or injuries. At the time of the accident, visibility conditions were dark and clear; the weather was 10°F with no precipitation.
The train was still traveling near maximum allowable speed at the time the 23rd car passed MP 49.81, so they hadn't really slowed the train at that point, and head end is probably more than 1200 ft (366 m) beyond that point. I'd estimate derailment about 2 miles from the detector. Hard to tell without knowing the deceleration. Freight car lengths vary, typically 53-65 ft (16-20 m), but some tank cars are shorter if they carry dense commodities like sulfuric acid. The length of the vinyl chloride tank cars were on the order of 53 ft (16 m) coupler to coupler.Train 32N comprised 2 head-end locomotives, 149 railcars, and 1 distributed power locomotive located between railcars 109 and 110. The consist included 20 placarded hazardous materials tank cars transporting combustible liquids, flammable liquids, and flammable gas, including vinyl chloride. Train 32N was traveling about 47 mph at the time of the derailment, which was less than the maximum authorized timetable speed of 50 mph.
So 38 cars derailed starting with the 23rd freight car through the 60th car (and may be the 61st as well). Five derailed DOT-105 specification tank cars (railcars 28–31 and 55) carrying 115,580 gallons of vinyl chloride (about 23,116 gal per tank car)
On the Fort Wayne Line of the Keystone Division, NS has equipped their rail network with HBD systems to assess the temperature conditions of wheel bearings while en route. The function of the HBD is to detect overheated bearings and provide audible real-time warnings to train crews. Train 32N passed three HBD systems on its trip before the derailment. At MP 79.9, the suspect bearing from the 23rd car had a recorded temperature of 38°F above ambient temperature. When train 32N passed the next HBD, at MP 69.01, the bearing’s recorded temperature was 103°F above ambient. The third HBD, at MP 49.81, recorded the suspect bearing’s temperature at 253°F above ambient. NS has established the following HBD alarm thresholds (above ambient temperature) and criteria for bearings:
- Between 170°F and 200°F, warm bearing (non-critical); stop and inspect
- A difference between bearings on the same axle greater than or equal to 115°F (non-critical); stop and inspect
- Greater than 200°F (critical); set out railcar
After the train stopped, the crew observed fire and smoke and notified the Cleveland East dispatcher of a possible derailment.
NTSB/FRA will have to look at these restrictions in light of an axle that failed catastrophically before the train was stopped. Tank car design will probably be considered as well.
A posted video shows sparks from the wheels (IIRC, the lead truck/bogie) of the 23rd car, a covered hopper car. One narration claimed the video was taken about 20 miles before the derailment, which would put the video near the HBD detector at MP 69.01. I don't know if that is true.
More details will come as information is verified.HBD = Hot Box Dectector (old term) or Hot Bearing Detector (modern term). Hot box originated when freight car trucks had journal (friction) bearings and the boxes formed in the cast steel frame held lubricant. Modern freight trucks (wheel sets) use sealed roller-bearings. I used to help my grandfather oil/lubricate journal bearings on freight cars back during the 1960s, before such equipment was phased out for roller bearings.
Maps care of USA Today
https://www.usatoday.com/story/grap...railment-ohio-explained-graphics/11251530002/
For those interested in Code of Federal Regulations on tank cars
https://www.govinfo.gov/content/pkg/CFR-2012-title49-vol3/xml/CFR-2012-title49-vol3-part179.xml
Some vinyl chloride tank cars may carry nearly 26k gallons.
https://www.gbrx.com/railcars/25800-gallon-vcm-pressure-tank-car/