An eight-car commuter train derailed early Monday at Chicago's O'Hare International Airport, injuring 32 people on board after it failed to stop at an underground station at one of the busiest airports in the United States.
Chicago Fire Commissioner Jose Santiago said the train ``climbed over the last stop, jumped up on the sidewalk and then went up the stairs and escalator.''
Chicago Transit Authority spokesman Brian Steele said authorities are trying to piece together what happened, but says the train was likely travelling too fast.
The derailment happened around 2:50 a.m.
Investigators aren't sure how many people were on board, but say none of the injuries are believed to be life-threatening.
The President of the Chicago transit union says there is some indication that fatigue could have played a roll in the crash.
The driver had told the union that she had worked a lot of overtime recently and was 'extremely tired' at the time of the derailment.