This photo released Tuesday, March 25, 2014, by the National Transportation Safety Board shows the aftermath of a Chicago commuter train that crashed Monday at O'Hare International Airport when the train jumped off the tracks and climbed an escalator. An NTSB official said Wednesday that the operator of the train admitted she "dozed off" before the accident. (AP Photo/Courtesy of the National Transportation Safety Board)
Tim DePaepe, an investigator with the National Transportation Safety Board, accompanied by Chicago Transit Authority President Forrest Claypool, right, speaks during a news conference Monday, March 24, 2014, at Chicago’s O’Hare International Airport in Chicago. The NTSB is leading an investigation into why an eight-car Chicago public-transit train jumped the tracks, skidded across a platform and scaled an escalator that leads to one of the nation's busiest airports early Monday, injuring 32 people. (AP Photo/Carla K. Johnson)
Dennis Hogenson, deputy regional chief of the National Transportation Safety Board's Western Pacific region, talks to reporters, Wednesday, March 19, 2014, in Federal Way, Wash., about the investigation into the crash of a news helicopter after it took off from a helipad at KOMO-TV on Tuesday, killing two people in the helicopter and injuring one person on the ground. (AP Photo/Ted S. Warren)
KOMO-TV photographer Jim Resch films Dennis Hogenson, deputy regional chief of the National Transportation Safety Board's Western Pacific region, as Hogenson talks to reporters, Wednesday, March 19, 2014, in Federal Way, Wash., about the investigation into the crash of a news helicopter after it took off from a helipad at KOMO-TV on Tuesday, killing two people in the helicopter and injuring one person on the ground. (AP Photo/Ted S. Warren)
FILE - In this Dec. 30, 2013 file photo, a fireball goes up at the site of an oil train derailment in Casselton, N.D. Rail cars being used to ship crude oil from North Dakota's Bakken region are an "unacceptable public risk," and even cars voluntarily upgraded by the industry may not be sufficient, a member of the National Transportation Safety Board said Wednesday, Feb. 16, 2014. The cars, known as DOT-111s, were involved in derailments of oil trains in Casselton, N.D., and Lac-Megantic, Quebec, just across the U.S. border, NTSB member Robert Sumwalt said at a House Transportation subcommittee hearing. (AP Photo/Bruce Crummy, File)
FILE - In this June 17, 2012, file photo, a replica of the historic ship HMS Bounty, is moored beside the U.S. Naval Academy in Annapolis, M.D. The National Transportation Safety Board says the former captain of a replica 18th-century sailing ship that sank off North Carolina during Hurricane Sandy made a reckless decision to sail into the storm. (AP Photo/Blake Sell, File)
National Edition News cover for December 27, 2013 - Safety data kept hidden from airline inspectors: A member of the National Transportation Safety Board investigating the emergency landing of Southwest Airlines Flight 812 cuts away a portion of the plane's fuselage on Sunday in Yuma, Ariz. (AP Photo)