A worker inspects the scene of an Amtrak train which derailed after striking a dump truck, Monday, June 27, 2022, near Mendon, Mo. (AP Photo/Charlie Riedel)

MENDON, Mo. — An Amtrak passenger train traveling from Los Angeles to Chicago struck a dump truck Monday in a remote area of Missouri, killing three people and injuring dozens more as rail cars tumbled off the tracks and landed on their sides, officials said.

Two of those killed were on the train and one was in the truck, Missouri State Highway Patrol spokesman Cpl. Justin Dunn said. It was not immediately clear exactly how many people were hurt, the patrol said, but hospitals reported receiving more than 40 patients from the crash and were expecting more.

Amtrak’s Southwest Chief was carrying about 207 passengers and crew members when the collision happened near Mendon at a rural intersection on a gravel road with no lights or electronic controls, according to the highway patrol. Officials were still trying to determine the exact number of people aboard. Seven cars derailed, the patrol said.

Rob Nightingale said he was dozing off in his sleeper compartment when the lights flickered and the train rocked back and forth.

“It was like slow motion. Then all of a sudden I felt it tip my way. I saw the ground coming toward my window, and all the debris and dust,” Nightingale told The Associated Press. “Then it sat on its side and it was complete silence. I sat there and didn’t hear anything. Then I heard a little girl next door crying.”

Nightingale was unhurt and he and other passengers were able to climb out of the overturned train car through a window.

The collision broke the dump truck apart, he said.

“It was all over the tracks,” said Nightingale, an art gallery owner from Taos, New Mexico, who said he rides Amtrak regularly to Chicago.

It’s too early to speculate on why the truck was on the tracks, said National Transportation Safety Board Chairwoman Jennifer Homendy. A team of NTSB investigators will arrive Tuesday, she said. Trains won’t be able to run on the track for “a matter of days” while they gather evidence, she added.

At one point, KMBC-TV helicopter video showed rail cars on their side as emergency responders used ladders to climb into one of them. Six medical helicopters parked nearby were waiting to transport patients.

Close to 20 local and state law enforcement agencies, ambulance services, fire department and medical helicopter services responded, Dunn said. The first emergency responders arrived within 20 minutes of receiving a 911 call, he said.

Passenger Dian Couture was in the dining car with her husband celebrating their 40th wedding anniversary when she heard a loud noise and the train wobbled and then crashed onto its side.

“The people on our left-hand side flew across and hit us, and then we were standing on the windows on the right-hand side of the car,” Couture told WDAF-TV. “Two gentlemen in the front came up, stacked a bunch of things and popped out the window and literally pulled us out by our hands.”