(CBS) -- Investigators are much closer to pinpointing the cause of Monday's CTA Blue Line collision involving a runaway train that was supposed to be standing still waiting for repairs.
CBS 2 Chief Correspondent Jay Levine reports.
'Ghost Train' Investigation
The National Transportation Safety Board and CTA investigators have virtually ruled out sabotage. And now they believe the runaway train actually stopped and started several times before the crash because of some kind of control problem.
A CTA bulletin posted Thursday in all train yards orders employees to isolate all defective cars and put chocks on all wheels to make sure the defective cars can't move.
The bulletin has led to concern among employees that the control problem may not be limited to the cars involved in the crash, but could be something that affects the computer control systems of other cars as well.
Witnesses, CBS 2 is told, have reported that the four-car train –- two defective cars and two others towing them -- stopped and started several times on the run from the Forest Park yard to the crash site at Harlem. The cars were stopped by the interlocks on both sides of the Forest Park Station, which worked as they should have, but then powered back up, starting up again apparently on their own.
Surveillance cameras showed no one was aboard the runaway train either that morning or the preceding 24 hours.
Thursday's bulletin caught CTA workers by surprise, something that probably wouldn't have happened had there not been a government shutdown and all the NTSB communications personnel on furlough.
The NTSB is well known as one of the most transparent government agencies, with daily briefings constantly updating investigators' findings.
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