An emergency stop system activated as it should have but failed to stop a Chicago Transit Authority train from jumping the platform and crashing into the escalators at the O'Hare International Airport station on Monday, a National Transportation Safety Board spokesman said.
"There is an automatic stop at the station that triggered the train and put it into emergency. It was attempting to stop the train. The brakes were applied," NTSB investigator-in-charge Ted Turpin said Tuesday in the agency's second press briefing regarding the crash.
"There's a physical device beside the track that the car activates, and that puts the train into emergency," he explained. "So it reached that point, and then the train went into emergency."
Further analysis was needed, Turpin said, to determine whether that mechanism activated in time, and the statement begs the question as to whether the safety measure was adequate or if the train simply overpowered it.
Forty-one station cameras, cameras on board each of the eight cars, and a forward-facing camera recorded video of the train entering the center train pocket of the station. Video from those cameras was in the process of being collected and will be sent to Washington, D.C. for analysis, Turpin said.
The speed limit entering the station is 25 miles per hour, and then immediately goes down to 15, employee union president Robert Kelly explained Monday. Turpin said the train involved in the crash came into the pocket at an "adequate" 25 or 26 MPH. The train's speed at impact, however, remained unknown.
"There's a lot of technical specifics to where the train should have stopped, and we still need to analyze that," said Turpin.
Kelly said Monday it appeared the train's motorman, who started her shift a little more than six hours before the incident, may have dozed off between the Rosemont and O'Hare stations, which are the final two stops on the Blue Line.
Turpin said officials would be conducting a 1 p.m. interview with that employee. Interviews have already been conducted with CTA management, he said.
Thirty-two people were injured -- but none seriously -- when the eight-car train continued through the end of the platform and struck the escalators leading to the airport terminals. The NTSB quickly took over the investigation of the crash and said mechanics, equipment and human factors would all be reviewed in order to determine the cause.
Turpin was hesitant to provide a firm deadline but said it may take about a week before the damaged train is removed and the trains and systems are again ready for use. That means the shuttle bus system in place between the Rosemont and O'Hare stations will continue for the foreseeable future.
When it comes time for crews to remove the train from the station, officials said they'll use torches to cut the damaged cars apart.