National Transportation Safety Board (NTSB) investigators said the Chicago Transit Authority's Blue Line station at O'Hare International Airport will not be up and running until this afternoon at the earliest, after a train jumped the tracks early Monday, injuring 32 people.

None of the injuries were serious.

News sources said the eight-car train failed to stop at the platform as scheduled. Instead, it continued through the end of the platform, jumped up on the sidewalk and struck the escalators leading to the airport terminals, according to authorities.

Robert Kelly, president of the Chicago Transit Authority union, said the train’s operator may have fallen asleep.

"She has worked a lot of hours in the past weekend, and the indication is there," said Kelly, although he noted that the female train operator had 17 hours off between her shifts.

Train operator will be questioned

At a news conference Monday, NTSB signal specialist Tim Depaepe said the operator will be interviewed when she is released from the hospital, where she was taken with leg injuries.

The ongoing investigation has forced the CTA to shuttle passengers between several busy stops by bus.

Train will be photo-documented

The NTSB said a priority was to put supports in place to ensure that the train doesn’t move and injure someone while investigators are photo-documenting the scene. The NTSB team includes experts in operations, mechanics, signaling, the track, and human factors.

Information will be gathered from video taken at the station and from a front-end, outward facing camera aboard the train and from "event recorders" in the CTA's signaling.