CASSELTON, N.D. – In releasing a long-awaited investigation report, the National Transportation Safety Board said a defective axle that broke was the likely cause of a fiery 2013 collision between an oil train and a derailed grain train just outside Casselton.

At an NTSB meeting Tuesday, Feb. 7, in Washington, D.C., crash investigators said the axle had an empty space in the center of it that should have been solid.

NTSB investigators learned that a Pennsylvania company, Standard Steel, made the flawed axle in 2002, among a total of 48 axles manufactured under similar conditions, investigator Michael Hiller said. Thirty-five of those axles, which may have similar defects, are not accounted for, he said.

“We can only assume that the axles have been removed from service due to life cycle, due to other accidents,” he said.

Hiller said 10 of the axles were found and taken out of service. It was discovered that two others were involved in separate accidents in 2010 in Nebraska, he said. No one was hurt in the two accidents, which were derailments that involved broken axles, according to Federal Railroad Administration records.

The Casselton collision between two BNSF trains happened on the afternoon of Dec. 30, 2013. It forced about 1,500 residents to evacuate their homes. No one was seriously injured.

Shortly afterward, NTSB investigators began focusing on the broken axle, which was on a derailed grain car. They found that the axle’s bearings and wheels were remounted by BNSF in 2010 and that more thorough testing of the axle would have caught the flaw.

The Association of American Railroads began requiring such testing of secondhand axles following an NTSB recommendation in April 2014, Hiller said. BNSF spokeswoman Amy McBeth said this sort of testing wasn’t standard practice in 2010.

The crash, which triggered massive explosions and received national media attention, highlighted the dangers of moving crude oil by rail. The tank cars involved were DOT-111s, which Congress has since required to eventually be replaced by more rugged DOT-117s that are believed to be safer.

“Yet the deadlines for replacing variants of the DOT-111 tank car, for carriage of various flammable liquids, fall along a timeline that extends from 2018 to 2029, leaving Americans at heightened risk for years to come,” said NTSB Chairman Christopher Hart. “While few DOT-111 tank cars remain in crude oil service, a vast fleet of these less safe tank cars continues in service for ethanol and other flammable liquids.”

McBeth said that since 2011, BNSF has “advocated for a new, stronger tank car standard and has worked with our customers to get safer tank cars into service sooner.”

The NTSB investigation found that after 13 cars from the westbound grain train derailed, the train’s emergency brakes were applied. At that point, the eastbound oil train was 18 seconds away, traveling at 42 mph. The oil train was likely moving at about that speed when it hit the grain car lying across the track, the NTSB said.

Twenty oil cars derailed, and 18 of those spilled more than 476,000 gallons of oil, fueling a fire that engulfed intact cars and caused them to explode, the NTSB said.

During Tuesday’s meeting, the NTSB showed a video of the crash, including the frantic radio traffic of an oil train crew member. "We are on fire," he told a train dispatcher. "We are derailed. We are all over. We got to go."

The front door of the oil train’s lead locomotive was damaged, so the two crew members narrowly escaped through a rear door shortly before the locomotive was engulfed in flames, the NTSB said.

Between the two lead locomotives of the oil train and the 104 tank cars was what’s called a buffer car that’s meant to protect the train crew from hazardous materials. In its investigation report, the NTSB recommended a study of whether more buffer cars should be required.

NTSB spokesman Eric Weiss has said the three-year-plus investigation into the crash took longer than usual because the agency used it as a vehicle to examine train safety features, such as advanced braking systems. Such braking systems, which can reduce stopping distance, would not have prevented the crash because only a few seconds passed between the time the oil train crew saw the derailed grain car and the moment of impact, Hart said.

The oil train engineer and conductor both sued BNSF after the crash. The conductor reached a confidential settlement with the railroad in July, and the engineer’s suit, which also targeted Standard Steel, is still pending.

Phone messages left for Standard Steel representatives were not returned Tuesday.

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