NORTH BERWICK (AP) — An Amtrak train smashed into a tractor-trailer Monday, killing the truck driver and injuring at least four others in an explosion that sent flames more than three stories high, a witness and officials said.

None of the train’s 112 passengers or two crew members suffered life-threatening injuries. The truck driver, whose identity wasn’t immediately released, was hauling trash to a landfill when he collided with the train about 11 a.m. in North Berwick, about 40 miles south of Portland.

Tom Gorski, who works in a building 50 yards from the intersection, said he heard the approaching locomotive, then a massive boom that shook the building.

He said he ran to the scene, where the truck’s cab was split with half on each side of the tracks. The ground was littered with trash from the tractor-trailer.

“It looked like somebody dropped a bomb. The flames were shooting higher than a three-story house,” said Gorski. “It brings tears to your eyes.”

There were skid marks on the road leading to the impact, suggesting the driver was trying to stop, Gorski said.

After the impact, the northbound train dragged the truck’s cab about 200 yards, then the train continued on before coming to a stop, said Deputy Fire Chief Larry Straffin.

The train’s engineer hopped off the locomotive and separated the burning engine from the passenger cars to keep the flames from spreading, Straffin said. Firefighters had to drag hose down the train tracks to douse the fire to the locomotive, he said.

It was unclear how many were injured. Amtrak said four people were hurt, and Straffin put the figure at six. Three were taken to Goodall Hospital in Sanford, where two were being treated for smoke inhalation and the third for a head injury, a spokeswoman said.

The locomotive was totally charred after the fire was extinguished, obscuring its markings, said Brianna Bataran, 17, of North Berwick. “You couldn’t even tell what kind of train it was.”

Service on the route was delayed after the collision. Nearly 1,400 passengers use the Portland-to-Boston service, which is operated by the Northern New England Passenger Rail Authority in Portland.

Last month, a man drove a semi-trailer into the side of a passenger train in Nevada in a fiery crash that killed six and injured more than 20. Amtrak is suing the Nevada trucking company the man worked for, alleging negligence in its training.