Three people are dead and at least 50 injured after an Amtrak train derailed Monday in Missouri, authorities said Monday evening.

Cpl. Justin Dunn, a spokesperson for Missouri State Highway Patrol Troop B, told reporters that two of the people who were killed were aboard the train while the third was in a dump truck that the train struck.

Authorities said the tragic incident happened at an uncontrolled intersection -- without warning lights or motion gates -- where a gravel road crossed the railroad tracks southwest of town.

Amtrak said the train collided with the dump truck at a public crossing near the city of Mendon at about 12:42 p.m. CT (1:42 p.m. ET).

Eight cars and two locomotives left the track “after striking a truck that was obstructing a public crossing near Mendon, Missouri,” company officials said in an updated statement. Dunn told reporters that seven cars had derailed.

Amtrak had said earlier that there were approximately 243 passengers and 12 crew members aboard the train.

A school has been turned into a triage center for victims with minor injuries, officials said.

A worker looks over the chassis of a dump truck hit by an Amtrak train on Monday.

Everything was in slow motion, passenger said

Robert Nightingale, a passenger with a sleeper car, said he was taking a nap when he heard something.

“It all happened like slow motion. It started to rock and, and rock, and then flicker, and then it just all of a sudden -- all this dust was through my window,” Nightingale, who is from Taos, New Mexico, told CNN.

He said the train fell over on the side that his compartment was on.

Nightingale, who was not injured, said he couldn't get through the window, which was blocked by dirt, so he grabbed his backpack and climbed into the hallway. Then he moved into a neighboring room where he found a way to climb out and onto the side of the train.

He said some people helped others reach the ground where he and others walked to the front of the train. He said the truck looked like it had big boulders in it.

“It hit something major to cause ... every car to go off,” he said.

Boy Scouts help the injured

Two Boy Scout troops from Appleton, Wisconsin, were on the Amtrak train and assisted people who were hurt, Scott Armstrong, director of national media for Boy Scouts of America, told CNN Monday.

Armstrong said the scouts on the train are believed to be between 14 and 17 years old and confirmed none of them were hurt. Eight adults were with the troops.

The two troops were on their way back from a stay at Philmont Scout Ranch in New Mexico, Armstrong said.

Second deadly collision in 2 days

Mendon is about 100 miles northeast of Kansas City. The train was traveling from Los Angeles to Chicago.

Amtrak said people who need immediate assistance with information about the train can call or text 1-800-USA-RAIL.

The National Transportation Safety Board is sending a 14-person team to the crash scene, the agency said in a tweet.

US Transportation Secretary Pete Buttigieg tweeted Monday evening that Federal Railroad Administration staff are en route to support the investigation.

Buttigieg tweeted, “Saddened by the tragic loss of life and injuries in the Missouri train derailment today & Northern California collision over the weekend.”

The collision was the second in two days in which an Amtrak train hit a passenger vehicle. On Sunday, 85 passengers were on board a train in rural California that hit a vehicle. Three people were killed and two people suffered major injuries, according to officials. All of the victims were in the vehicle, the officials added. (CNN)

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