Emergency braking system blamed in O'Hare train crash

CHICAGO (AP) - An emergency track-side braking system activated but failed to stop a Chicago commuter train from jumping the tracks and barreling to the top of an escalator at O'Hare International Airport, a federal investigator said Tuesday.

The events that led to Monday's accident, which occurred around 3 a.m. and injured more than 30 passengers, might have begun with the train operator dozing off toward the end of her shift, according the union representing transit workers. But Tuesday's announcement that a piece of emergency safety equipment might have failed was the first indication the accident could have been caused by human error and mechanical failure.

National Transportation Safety Board investigator Ted Turpin said a preliminary review showed the train was traveling at the correct speed of 25 mph as it entered the station. Investigators said they have not yet determined whether the operator ever applied the in-cab brake.

Turpin, who is in charge of the investigation, said an automatic emergency braking system located on the tracks was activated but failed to stop the train as it burst onto the platform.

"It activated," Turpin said of the emergency system. "That's all we know factually. Now, whether it did it in time or not, that's an analysis that we have to figure out."