WHITE SALMON, Wash. (AP) – The engine of an Amtrak train derailed Sunday along the Columbia River, sending at least 10 passengers to hospitals with mostly minor injuries, officials said.

The Portland, Ore.-bound train was carrying 115 people when the locomotive’s wheels left the track, leaving four passenger cars leaning upright against an embankment in the Columbia River Gorge, about 45 miles east of Portland, Ore., Amtrak spokeswoman Marcie Golgoski said.

Three people remained in hospitals Sunday afternoon, including a pregnant woman who was admitted for observation. Seven others, including a man with a shoulder injury, were treated and released.

Rail crews were clearing the track, but it was not expected to reopen until Monday, said Gus Melonas, a spokesman for BNSF Railway Co., which owns and operates the track.

By midday, passengers who could travel were loaded onto school buses and taken to Vancouver, Wash., and Portland, Ore.

The National Transportation Safety Board and BNSF were investigating the cause of the accident.