It appears federal investigators are now focused on a technical malfunction, not a human act, as the cause of Monday's accident on the CTA Blue Line.
A bulletin went out to CTA employees Thursday night outlining new procedures for handling cars that are taken out of service. In Monday's incident, two out-of-service cars, hooked to two good cars, hurtled out of control from the Forest Park yard, colliding with an outbound train at the Harlem Avenue station.
CTA spokesman Brian Steele confirms the advisory, known as a "General Bulletin", went out this evening. But Steele insisted that the new procedures were initiated at the CTA, not at the insistence or recommendation of federal investigators. He would not comment on how the federal authorities may be leaning in their investigation.
Among the procedures outlined in the bulletin for "cars on hold" in CTA yards:
- Insuring all parking brakes are put in the "applied" position.
- Disengaging electric coupler buttons, which allow power to flow between cars which have been physically hooked together. Those must be retracted.
- Clearly marking out-of-service train sets with blue and white "tags" on the front and tail end of each unit.
"This is solely CTA's decision," Steele said. "This is belt, suspenders, and another belt."
Still, a source close to the investigation, who asked not to be identified because of the ongoing federal probe, said while nothing has been ruled out officially, this evening's bulletin makes clear that investigators are now leaning toward an incident which was not due to foul play. And in the words of the source, "This was not human error."
It is not unusual for trains to be idling in the yard, unattended. While it may run contrary to official policy, insiders say allowing cars to idle is often done to keep them warm on cool evenings, or cooler in the summer. In this particular case, the two out-of-service cars, which were hooked to two forward "horse" cars (which were to pull them to the Skokie maintenance shops), somehow managed to engage and move forward, overpowering the ability of the two good cars to stop them.
"It was a malfunction," said the source. "The riders are not at any risk".
It should be noted that the current approach represents theories which are being developed at a point which should still be considered early in the investigation.
Investigators reportedly now hypothesize that the fail-safe systems on the CTA, including at least two switches the train rolled over, did try to stop the train. In other words, the two horse cars were trying to brake and stop, but the two malfunctioning cars drove them forward.
One observer said as bad as the accident was, it could have been worse. Had the two malfunctioning cars rolled on their own, without the "horse" cars trying to stop them, they might have been traveling at a much higher speed.
Steele would not comment. But he said while the new procedures were officially in place as of this evening, it remains to be seen whether they will become permanent, pending the outcome of the ongoing NTSB investigation.