At 1:42 p.m., Amtrak said the train collided with a truck at a public intersection near the town of CT Menton.
Dunn said authorities are still trying to determine the exact number of dead. Two of those killed were on the train and the third was in the truck, Dunn told a news conference.
Eight cars and two engines left the track “after hitting a truck that was obstructing a public crossing near Mendon, Missouri,” company officials said in an updated statement.
Amtrak had previously said the train had about 243 passengers and 12 crew on board.
A school has been converted into a treatment center for victims with minor injuries, he said.
Authorities said the train collided with a tipper truck.
Everything was in slow motion, passengers said
Robert Nightingale, who was traveling in a sleeper car, said he was asleep when he heard something.
“It all happened like slow motion. It started playing, and it started playing, and then it started flashing, and then all of a sudden – all this dust was through my window,” said Nightingale, of Davos, New Mexico. Told CNN.
He said the train fell on the side where his box was.
The uninjured Nightingale could not go through the dirty window, so he grabbed his backpack and climbed the sidewalk. Then he went to an adjoining room, where he found a way to get out and get on the side of the train.
He said he and others helped some others reach the ground in front of the train. That said it looks like there are big rocks in the truck.
“It hit something big … every car had to leave,” he said.
Menton is located 100 miles northeast of Kansas City. The train was going from Los Angeles to Chicago.
Those who need immediate assistance with information about the train can call 1-800-USA-RAIL or send an SMS, Amtrak said.
It is a growing story and will be updated.
CNN’s Andi Babineau contributed to this report.
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