CHICAGO (CBS) -- A commute into the city took a horrible turn Thursday, as a CTA Yellow Line, or Skokie Swift, train slammed into a snowplow on the tracks on its way into the Howard terminal in Rogers Park.
– which happened as the tracks curve southeast from a trench that runs through southern Evanston into the Howard rail yard.
The crash caused the lead-end wheel set of the Yellow Line train to derail. The snow-fighting unit also sustained some damage to the back, and the Fire Department said the person operating the snow fighter was also seriously hurt.
As CBS 2's Marybel González reported Thursday night, new audio we obtained late Thursday appears to show that some were aware the snowplow was on the tracks – and even tried to issue a warning.
What happened following that – and right before the crash – still remains to be determined.
"Control operator 591, 591 – stop your train, please," someone is heard saying in the Chicago Transit Authority control tower.
A little over a minute later, the same person in the control tower said, "They have made contact with some equipment at Chicago – the rear of the equipment – which has caused injuries on the train at this time."
Audio from the CTA control tower we obtained shows another warning possibly came even earlier – more than an hour before the two-car Yellow Line train traveling inbound toward the Howard terminal would slam into a CTA snow fighter locomotive at around 10:30 a.m. Thursday.
"Make sure you get the attention of the personnel - once again, that's from Howard to Oakton," someone says in the control tower. "Personnel is on the right-of-way."
The CTA has not explained why the machine used to clear the tracks of snow in the wintertime was on the tracks.
Joe Schwieterman, a professor at DePaul University and an expert in the field of transportation, weighed in on
"For accidents like this to happen, you need multiple things to occur," Schwieterman said. "Why those signals didn't turn red, or the motorman ran right through that – and typically, you slow down coming into the Howard station maybe to 25. The top speed on the Swift is 55. But boy, that's a worst-case scenario – right around that curve, not enough time to stop, and usually, visual cues are enough to stop an 'L' train. But not today."
The placement of the snow fighter is also a concern.
"If trains hit, you know, sort of bumper-to-bumper, frame-to-frame, it's a lot less devastating here than having this odd-shaped equipment - which punctured the front of that train," Schwieterman said.
The collision injured all 38 people – 31 passengers and seven CTA staffers – onboard. Of those 38 people, 23 ended up in the hospital.
None of the accident victims suffered life-threatening injuries, according to the Chicago Fire Department.
Now, some lawmakers are also calling for an investigation, including Illinois state Rep. Kam Buckner (D-Chicago).
Buckner said he wants a probe into "how we got here - what happened. "What occurred to make this collision possible? What are things we could have done differently?"
We have also taken those questions to the CTA, but there had been no answers as of 10 p.m.
The National Transportation Safety Board is investigating, with a team on the way to Chicago Thursday night that is expected to arrive on Friday morning. They also plan to hold a briefing about the crash Friday afternoon.
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