HANFORD  (AP) — At least 20 passengers suffered minor to moderate injuries Monday when a big rig truck collided with a southbound Amtrak train in California's Central Valley, authorities said.

The crash occurred when the driver of the big rig that was carrying cotton trash failed to yield and hit the train, pushing at least one passenger car off the tracks south of Hanford, authorities said.

The injuries were described as bumps, bruises, scrapes and possibly broken bones by Kings County Assistant Sheriff Dave Putnam.

The crash occurred at a crossing that was equipped with control gates, Putnam said.

Six of the injured passengers were taken to Adventist Medical Center in Hanford, said hospital spokeswoman Christine Pickering. She did not provide details on the extent of their injuries.

"We did call in additional physicians and staff," Pickering said.

The train carrying about 169 passengers and four crew members was on its way from Oakland to Bakersfield, according to Amtrak. It had four rail cars and a locomotive.

The truck driver suffered minor injuries, according to California Highway Patrol spokesman Jerry Pierce. The CHP will investigate the crash.

"This is a big, huge chaotic scene with lots of agencies involved," Pierce said.

Pierce said the other passengers have been taken to an auditorium in Hanford, where they will board a train and continue to their destinations or family members will pick them up.