(Reuters) - The operator of a passenger train that jumped the tracks and ran part-way up an escalator at Chicago's O'Hare International Airport early on Monday admitted that she dozed off and did not wake up until the crash, a federal investigator said.
The operator had been running Chicago Transit Authority (CTA) trains for about 60 days before the incident and was admonished in February for overrunning a station, Ted Turpin, an investigator for the National Transportation Safety Board, said on Wednesday.
In the February incident, the operator told investigators she "closed her eyes for a moment," the CTA said. One train car had extended beyond a station platform, the report said.
"This time she woke up when she hit," Turpin said, referring to the crash at 3 a.m. CDT (0800 GMT) Monday at the end of the line at the O'Hare station.
The operator had started her shift at about 10 p.m. the previous night and was on the fourth of five round trips running the electric, elevated train, he said.
Turpin said the operator told investigators she dozed off before the train entered the airport transit station and did not wake up until the train hit close to the end of the bumper.
The CTA said the operator is on "injured duty status" and that discipline, up to discharge, is allowed for this type of incident, which was her second safety violation.
The NTSB and CTA did not identify the operator.
More than 30 people on board suffered injuries that were not believed to be life threatening, and attorneys have begun filing lawsuits on behalf of some of the passengers.
The NTSB has said the train was traveling at about 26 mph when it entered the station, and tripped an emergency braking system beside the track before impact.
Turpin said the NTSB would examine the mechanisms in place for emergency braking and the approved stopping distance, as well as looking at station-design plans.
The trip stop that activates emergency braking is 41 feet from the bumper, Turpin said. Investigators have not determined how fast the train was moving at impact, or how well the braking worked, he said.
The CTA said it would lower the speed limit for trains entering the station to 15 mph and move up the trip switches to engage emergency braking earlier on trains exceeding the limit.
The NTSB has released the crash site to the CTA, which said it hopes to restore service by the weekend. The CTA, in the meantime, is running shuttle buses between the airport and its next rail station.
Monday's crash was the second in recent months involving an apparently out-of-control CTA train. In September, an unmanned CTA train ran onto active tracks and collided with a standing train at a suburban Chicago station during the morning rush hour, injuring at least 33 people.
Separately, after a deadly derailment of a New York commuter train late last year, an engineer told investigators he became dazed and lost focus before the train, traveling at nearly three times the speed limit, hurtled off the tracks near the end of its run. Four people died and more than 70 were injured.
Reporting by David Bailey in Minneapolis; Editing by Colleen Jenkins, Bernadette Baum and Gunna Dickson