An automatic braking system like one scheduled to be installed by next year on some railroads might have helped stop a CTA train Monday morning from taking a bizarre leap off the tracks and onto an escalator at O'Hare International Airport, investigators say.
But they're also looking into why safety measures already in place did not prevent the crash, which injured 32 people at about 2:50 a.m. Monday.
A transit union official said the train operator "might have dozed off" in the moments before the crash.
National Transportation Safety Board investigators will be examining the human, technical and mechanical issues in the derailment that has closed the O'Hare CTA station until further notice.
Asked about prevention, NTSB investigator Tim DePaepe noted positive train control, set to be installed by next year on many railroads nationwide, is designed to automatically stop or slow trains before accidents. But it is costly.
"It's about money," he added. "The transit agencies do the best with what they have."
Human factors will be another focus for investigators. Amalgamated Transit Union Local 308 President Robert Kelly said the operator of the Blue Line train told him she had worked a lot of overtime recently and was "extremely tired." She started her shift at 8:40 p.m., about six hours before the crash.
She "might have dozed off," Kelly said. But the operator, who has worked for the CTA for about a year, had about 16 hours between shifts, he said.
The train operator suffered a leg injury, Kelly said.
The derailment propelled the train's head car off the tracks, onto the platform and partially onto the escalator. A second car was lifted up by the momentum of the head car, officials said.
Thirty-two passengers were taken to local hospitals with minor physical injuries but with mental trauma, authorities said.
CTA officials couldn't say how long the O'Hare station will remain closed. On-scene evidence collection takes four to nine days in general, DePaepe said. In the meantime, shuttles will run between O'Hare and Rosemont every five to six minutes.
Investigators will also review a video from the front of the train, as well as signal recordings.
"I've investigated many accidents ... many trains do different things," DePaepe said. "It's all about kinetic forces, but I have not seen an accident like this."
In addition to interviewing the operator, the NTSB will look at the signal system, the brakes, communications, the tracks and other equipment and safety technology intended to prevent such a crash. Officials could not say Monday how fast the train was traveling.
Safeguards, however, are in place to prevent the type of crash that occurred, experts said. A system of signals and switches as the train approaches the station can cut power if abnormal conditions exist.
Also, stop arms are track-side levers that apply brakes to trains if they're traveling at the wrong speed or switches aren't aligned.
Trains also have a so-called "deadman's switch" that can cut power automatically if the engineer is incapacitated.
Investigators will work to determine whether those systems were operating as they should.
In addition, since O'Hare is the terminus of the Blue Line, a massive "bumping post" made of steel and rubber lies at the end of the tracks intended to stop cars. But the train's lead car appeared to have leapt over that.
Bewildered passengers waiting on a shuttle bus outside O'Hare International Airport Monday morning speculated on the cause of the crash.
"You'd think they'd have some type of braking system to stop this from happening," Chicagoan Chris Schamberger said. "That's crazy. To go so fast you go up (an escalator) ... that's insane."
CTA has no mandate to install positive train control. Metra is supposed to meet the 2015 deadline but in the past has indicated limited funds are making it difficult to do so. Estimates for installing the system at Metra are about $214 million.
The Rosemont CTA station was on overdrive Monday afternoon with a cavalcade of shuttle buses arriving from O'Hare and heading back. "It's like something out of a 'Transformers' movie," said Chris Popiwchak, who works in Rosemont. "This station was crazy this morning."
Most of the injured passengers worked at O'Hare or for the U.S. Department of Homeland Security.
The crash came during one of the CTA's lowest ridership periods, spokesman Brian Steele said.
Service is running as usual from Rosemont to Forest Park, CTA President Forrest Claypool said.
Those injured were taken to Our Lady of Resurrection Hospital, Lutheran General Hospital and Swedish Covenant Hospital with "bruises and a lot of anxiety," Chicago Fire Department spokesman Larry Langford said.
• Daily Herald staff writer Jessica Cilella contributed to this report.