Updated 03/24/14 - 4:30 p.m.
CHICAGO (CBS) -- The operator of the CTA Blue Line train told union officials that she dozed off before the train jumped the tracks and slammed into an escalator early Monday morning at the O'Hare station.
Two sources told CBS 2 that the operator has signed a statement acknowledging she did fall asleep briefly.
The train approached the bumping post at a speed between 15 and 25 miles an hour, the source tells CBS2.
The train should have been slowing from a crawl to a stop.
It appears the "track trips" worked, the source said. These are a series of metal bars that rise up when a sensor determines the approaching train is coming in too fast for conditions.
The mass of the 320,000 pound train appears to have blown right past the first of two of these trips.
Earlier Monday, federal authorities said it's too soon to tell how fast the train was going when it derailed at O'Hare International Airport early Monday, or why the train failed to slow down, and ended up jumping the tracks, and crashing into the escalator.
A six-person team from the National Transportation Safety Board will be investigating the cause of the derailment, which happened just before 3 a.m.
Officials said an eight-car train failed to stop as it pulled into the O'Hare station, and jumped the tracks, went onto the platform, then went up the escalator, stopping just short of the turnstiles.
Thirty-seven people, including the train operator, were injured in the crash. All had been released from local hospitals by late Monday evening.
NTSB rail investigator Tim DePaepe said it was too early for investigators to know exactly how fast the train was going when it crashed through a bumper at the end of the tracks, and slammed into an escalator. He said investigators would be examining the train, tracks, signals, and other equipment, as well as looking at the possibility of human error in determining what happened.
DePaepe said the NTSB would review surveillance video recorded by cameras inside and outside the train as part of their investigation, to help determine how fast the train was going.
Robert Kelly, president of Amalgamated Transit Union Local 308 -- which represents approximately 3,500 CTA workers -- said, although it has not yet been ruled out whether the train operator made any mistakes while pulling into the station, Kelly said automated systems should have stopped the train if the operator did not hit the brakes in time. The woman who was operating the train has been at the CTA for about a year.
DePaepe said it was too early to know if there was a malfunction in automated systems designed to stop the train if the operator does not hit the brakes in time. He noted it's possible there was also a signal error, or that the brakes themselves malfunctioned.
NTSB investigators had not yet interviewed the train operator as of noon Monday, according to DePaepe.
Blue Line Train Jumps Tracks, Slams Into Escalator At O'Hare
CTA spokesman Brian Steele said the train was going faster than normal when it was pulling into the station, and did not slow down before it derailed.
One passenger described what she experienced when the train crashed.
"I heard a boom, and when I got off the train, the train was all the way up the escalator. It's a wreck," Denise Adams said. "Ain't nothing going to move out of that station today, period, because that train, it's going to take a while to get that train off that escalator."
Chicago Fire Department Commissioner Jose Santiago said 32 people were taken to four different hospitals. None of the injuries appeared to be life-threatening.
The train operator was released from the hospital late Monday morning.
The two front cars of the train were severely damaged in the crash. DePaepe said the damaged train would not be removed from the station until NTSB investigators can examine it. He said it likely would be at least 24 hours until the train could be moved.
"The train is not going to go anywhere for the foreseeable future. It's not going to go anywhere today," DePaepe said.
NTSB Investigating Cause Of Blue Line Crash
The O'Hare station was shut down after the crash, and the CTA was running bus shuttles in both directions between O'Hare and the Rosemont stop. Those buses were departing Rosemont and O'Hare every 5 to 6 minutes, according to CTA President Forrest Claypool.
The rest of the Blue Line -- between Rosemont and Forest Park -- was running roughly on schedule, Claypool said. Most passengers who were taking bus shuttles said it was only a minor inconvenience that delayed them a few minutes.
CTA officials said the O'Hare station would remain closed until crews can remove the damaged train and clean up debris from the crash.
"We'll break the train apart, move the train out – the majority of the train out – and back towards Rosemont," CTA chief infrastructure officer Chris Bushell said. "Of course, once we move the train, we'll have a much clearer picture of what the issues are there."
The crash happened nearly six months after another major derailment along the Blue Line. On Sept 30, a "ghost train" with no operator traveled for about a mile along the Blue Line before slamming into another train at the Harlem station in Forest Park.
At least 33 people were hurt in that crash. The CTA fired two electricians for leaving doors open after working on the boxes, which allowed water to get inside during a subsequent power wash. Three days later, the controls failed and the train crashed.
Travelers who were taking the shuttle buses between the Rosemont station and O'Hare gave positive reviews, CBS 2's Jim Williams reports.
Keli Bushong said CTA employees were giving directions at both the Rosemont station and O'Hare.
"We flew in from Phoenix. They had lots of people helping us and directing us at every turn," Bushong said.
The shuttles have no schedule. Passengers pack the buses, and they take off. Expect to add at least 10 more minutes to your trip.
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