CHICAGO — More than 30 people were injured this morning when a Chicago Transit Authority train jumped the platform and climbed up an escalator at the end of the Blue Line at O’Hare International Airport, officials said.

“I heard a boom and when I got off the train, the train was all the way up the escalator. It’s a wreck,” Denise Adams, who was riding toward the back of the train. “It was a lot of panic because it was hard to get people off the train.”

Fire crews scrambled to determine if anyone was underneath the train but no one was found, according to Chicago Fire Commissioner Joe Santiago. All of the injured were aboard the train and were taken in fair or good condition to four hospitals, he said.

The operator of the train “was walking and talking as we were investigating,” Santiago said.

The eight-car train was wedged near the top of an escalator used by commuters at the Blue Line terminal. CTA spokesman Brian Steele said workers may have to cut up the car and remove it piece by piece, which could take 12 to 24 hours.

Then the damage will have to be assessed and repairs made before trains use the station, he said.

In the meantime, shuttle buses will be used between Rosemont, Ill., and O’Hare.

Steele said the cause of the accident remained under investigation.