EASTON, Kan. (WDAF) — An investigation is underway after three people were killed and at least 50 injured after an Amtrak Southwest Chief train hit a dump truck at a public crossing and derailed near Mendon, north of Marshall, Missouri, Monday afternoon.

The derailment happened about 100 miles northeast of Kansas City or about two hours by car. The Missouri State Highway Patrol said eight cars were affected; seven derailed.

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.

The Easton, Kansas School District (USD 449) said six students and two chaperones were on the train on their way to Chicago to represent Pleasant Ridge High School in Leavenworth County at the Future Business Leaders of America National Convention.

The school district said it has been in contact with all parents involved as well as the chaperones.

“Our PRHS Rams, along with the chaperones, are okay and have been reunited with their families,” the school district posted on Facebook Monday evening. “Our thoughts and prayers go out to all those involved.”

Passengers also included 16 youths and eight adults from two Boy Scout troops who were traveling home to Appleton, Wisconsin, after a backcountry excursion at the Philmont Scout Ranch in New Mexico.

Dan Skrypczak, Appleton Troop 73 Scout Master, confirmed that two adults from the group were taken to the hospital by ambulance with minor injuries.

Along with the two adults, two scouts were also taken to be checked out. Skrypczak also said that six scouts and four adults from the two troops stayed back to help the situation.

Amtrak’s Southwest Chief was carrying about 243 passengers and 12 crew members when the collision happened near Mendon at a rural intersection on a gravel road with no lights or electronic controls, officials said. Seven cars derailed, the patrol said.

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 run be able to run on the track for “a matter of days” while they gather evidence, she added.

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