HELENA, Mont. >> Poor track conditions that should have been flagged by a freight railroad company’s inspectors caused the derailment of an Amtrak train in Montana that killed three people and injured 49 others in 2021, federal investigators said Thursday in a final report.

The severity of the injuries were made worse by the Amtrak train’s lack of seatbelts and windows that weren’t strong enough to keep passengers from being ejected when the train derailed, the National Transportation Safety Board found.

Amtrak’s Empire Builder derailed Sept. 25, 2021, in northern Montana while it was en route from Chicago to Seattle and Portland, Oregon, with 165 people on board, including its crew. It was traveling on tracks owned by BNSF Railway.

Six people were ejected from the train’s observation car, which has larger windows and was one of three cars that ended up on its side. One person who had been riding in the observation car died, as did two people who were in the vestibule between the observation car and the car behind it, the NTSB said.

Had the combination of wear and damage to the railroad track been noticed by BNSF Railway inspectors, the railroad would have been able to address the issue before the derailment occurred, the report found. Investigators also found that a train inspector’s workload likely prevented him from doing a timely walking inspection of the area before the derailment.

That inspector had worked an average of 13 hours a day in the four weeks prior to the incident, and the last walking inspection of the area had been done two years before the derailment, the report found.

The inspector had noticed problems with the joints on the tracks during a riding inspection two days before the derailment, but he and a manager didn’t stop to check out the joints. BNSF had also ordered trains to go no faster than 50 mph in that area seven times in the two months before the derailment — a period in which it was replacing railroad ties.

The poor track conditions included a worn rail, vertical track deflection, misalignment and instability in the rail bed, the report found. The NTSB said BNSF’s lack of action indicated “a shortcoming in its safety culture.”

“This tragedy is a powerful reminder that there’s no substitute for robust track inspection practices, which can prevent derailments by identifying track conditions that may deteriorate over time,” said NTSB Chair Jennifer Homendy.

BNSF railroad spokesperson Lena Kent defended the company’s inspection record and touted its use of advanced technology that alerts personnel to dangerous track conditions.

“We are committed to timely maintenance, repair and replacement whenever issues or potential issues are detected,” Kent said in an emailed statement.

Marc Magliari, a spokesperson for Amtrak, said in a statement that “Amtrak appreciates the opportunity to participate in the investigation and we will review the recommendations. Amtrak will continue to work with all stakeholders to improve rail safety for the traveling public.”

Kristofer Riddle, an attorney for four passengers who were on the train, said he was unsurprised by the report’s findings because damaged tracks are well-known safety concerns.

What continues to outrage him, he said, is that the same safety concerns arise after passenger train accidents without any changes. One of his clients, Justin Ruddell, was in a train car restroom when it derailed near the small town of Joplin, whipping the door open and pouring dirt and gravel atop him as he clung for dear life.

“The thing here that’s particularly egregious is this is the story that you hear after derailments time and time again,” Riddle said.

Railroad safety expert Dave Clarke, a former director of the Center for Transportation Research at the University of Tennessee, said it probably wasn’t practical for the inspector to regularly walk the track because he had such a large area to cover each day, but that walking inspections aren’t typically done all that often.

Also, it would have been hard for the inspector to identify that this combination of problems might cause a derailment because none of these issues were severe enough to be considered a defect by the Federal Railroad Administration, which regulates railroad safety. He said it would have been a judgment call for the inspector to say this combination of factors was dangerous.

“If you’ve got 50 or 60 miles to cover in a day, you’re not going to walk the track other than in specific spots where you need to cover something,” Clarke said.

Investigators also found that if a locomotive equipped with an automated vehicle-track interaction monitoring system had traveled over the area, it might have detected the deteriorating track conditions and BNSF would have had an opportunity to make repairs, or at least issue a warning to train crews to travel slowly through the area. The NTSB is recommending that all trains be equipped with that technology.

Thursday’s finding follows what was revealed earlier this year in the agency’s investigative documents. Investigators identified a deteriorating track based on video footage from three eastbound trains, including another Amtrak train, that traveled through the area in the hours before the westbound Amtrak train’s derailment.

The problem got worse as the trains traveled over the area before the crash, the report said.

An image from video captured by the derailed train showed a nearly 3-inch (23-centimeter) misalignment in the rails, the report said.

Killed in the accident were Margie and Don Varnadoe, a Georgia couple on a cross-country trip to mark their 50th wedding anniversary, and Zachariah Schneider, 28, a software developer from Illinois.

Families of those who were killed and injured passengers have filed lawsuits against BSNF and against Amtrak.

BNSF is owned by Warren Buffett’s Omaha, Nebraska-based Berkshire Hathaway conglomerate.

Railroad unions have expressed concerns that the lean operating model all the major freight railroads have adopted has made railroads riskier because employees are spread so thin and some workers have to take care of such large territories that it’s hard to keep up with preventative maintenance.

The railroads have defended their practices and don’t believe they have sacrificed safety when they streamlined operations.

Railroad safety has become a hot topic this year in the wake of a fiery Ohio derailment in February and several other crashes that prompted regulators and members of Congress to propose a series of reforms.

Metz reported from Salt Lake City. Associated Press writer Josh Funk contributed to this report from Omaha, Nebraska.