Three people have been killed and dozens more injured after a passenger train travelling from Los Angeles to Chicago struck a lorry and derailed in a remote area of Missouri, officials said.

Two of those killed were on the Amtrak train and one was in the lorry, said Missouri State Highway Patrol spokesman corporal Justin Dunn.

Hospitals reported receiving more than 40 patients from the crash and were expecting more after carriages tumbled off the tracks and landed on their sides.

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 are still trying to determine the exact number of people on board. Seven carriages 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 towards my window, and all the debris and dust," Mr Nightingale said. "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."

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

The collision broke the lorry apart, he said.

"It was all over the tracks," said Mr Nightingale, an art gallery owner from New Mexico, who said he regularly travels on Amtrak services to Chicago.

It is too early to speculate on why the lorry was on the tracks, said National Transportation Safety Board (NTSB) chairwoman Jennifer Homendy.

A team of NTSB investigators will arrive on Tuesday, she said. Trains will not be able to run on the track for "a matter of days" while they gather evidence, she added.

Passenger Dian Couture was in the dining carriage 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," Mrs Couture said. "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."

Mike Spencer, who grows corn and soybeans on the land surrounding the intersection where the crash occurred, said everyone in Mendon understands that the intersection is dangerous, especially for those driving heavy, slow farm equipment.

The approach to the tracks is on an inclining gravel road and it is difficult to see trains coming in either direction, he said.

Mr Spencer said he had contacted officials about the potential danger.

It was the second Amtrak collision in as many days. Three people in a car were killed on Sunday afternoon when an Amtrak commuter train smashed into it in Northern California, authorities said.

The Southwest Chief takes about two days to travel from Los Angeles to Chicago, picking up passengers at stops in between.

Mendon, with a population of about 160, is about 84 miles north-east of Kansas City.