About 2:49 a.m. on March 24, 2014, Chicago Transit Authority train No. 141 collided with the bumping post near the end of the center pocket track at O’Hare Station. The lead car rode over the bumping post and went up an escalator at the end of the track. The escalator provided public access to enter O’Hare International Airport from the platform in the station, but no one was using it at the time of the accident. About 50 people were on the train at the time of the accident. Thirty-three injured passengers and the injured train operator were taken to the hospital. The estimated damage was $11,196,796. The accident occurred in an underground station that was not impacted by weather conditions.
The National Transportation Safety Board determines that the probable cause of the accident was the failure of the train operator to stop the train at the appropriate signal due to falling asleep as a result of fatigue, which was the result of the challenges of working shiftwork, circadian factors, and acute sleep loss resulting from her ineffective off-duty time management. In addition, Chicago Transit Authority failed to effectively manage the operator’s work schedule to mitigate the risk of fatigue. Contributing to the severity of the accident was Chicago Transit Authority’s failure to identify the insufficient stopping distance and inadequate speed restriction at the center pocket track at O’Hare Station.