Amtrak confirmed that eight cars on the Seattle-bound Empire Builder train went off the rails near the town of Joplin at around 4pm on Saturday, with approximately 141 passengers and 16 crew members on board.
“We are deeply saddened to learn local authorities are now confirming that three people have lost their lives as a result of this accident,” the rail operator said in a statement on Saturday night.
“There are also reported injuries among the passengers and crew members traveling on the train.”
People trapped aboard soon after the derailment have all been taken off the train, an official at the Liberty County Sheriff’s Office told the Reuters news agency. The number of people injured has not been confirmed.
Photos posted to social media show train cars tipped over and passengers standing by the tracks with their luggage. The images showed sunny skies, and it appeared the accident occurred along a straight section of tracks.
Megan Vandervest, a passenger who was going to visit a friend in Seattle, told The New York Times that she was awakened by the derailment, describing it as feeling like “extreme turbulence on a plane”.
“My first thought was that we were derailing because, to be honest, I have anxiety and I had heard stories about trains derailing,” she said. “My second thought was that’s crazy. We wouldn’t be derailing. Like, that doesn’t happen.”
She told the newspaper that the car behind hers was tilted, the one behind that was tipped over, and the three cars behind that “had completely fallen off the tracks and were detached from the train.”
Residents of towns near the crash site quickly mobilised to help the passengers following the accident.
Chester Councilwoman Rachel Ghekiere said she and others helped about 50 to 60 passengers who were brought to a local school.
“I went to the school and assisted with water, food, wiping dirt off faces,” she said. “They appeared to be tired, shaken but happy that they were where they were. Some looked more disheveled than others, depending where they were on the train.”
The cause of the derailment was not clear but it will investigated by the National Transportation Safety Board (NTSB).
Eric Weiss, a spokesman for Amtrak, said the NTSB would send a 14-member team to the scene, including investigators and specialists in railroad signals and other disciplines.
No other trains or equipment were involved in the derailment, Mr Weiss said.
Additional reporting by Associated Press and Reuters.