The National Transportation Safety Board this weekend provided the first clues about what caused a CTA Yellow Line train to collide with a snowplow at nearly 30 mph near Howard Station on Thursday.
The operator took longer to brake than the train was designed for and the train’s wheels slipped due to debris on the tracks, the NTSB said Saturday.
But passengers and a transportation expert question the role of potential human error, including why the train was on the same track as a snowplow used to train CTA employees.
“It should never have happened,” said Stephen Helmer, who was on the train with his daughter and two grandchildren.
“We want answers as to why he was on the same track, at the same time and in the same place as the commuters,” he said.
NTSB Board Chair Jennifer Homendy told reporters Saturday that the operator did not appear to be distracted, but did not address the main question of why the train and plow shared the same track.
While the NTSB’s full report may take months to complete, some key questions still remain.
One is whether the operator ran a signal or there was a stop sign, said Joseph Schwieterman, a transportation professor at DePaul University.
There is also the question of whether the controller was alerted to the snowplow’s presence.
“Usually, there’s enough space, there wouldn’t be two trains in the same signal block,” Schwieterman said.
As for stopping distance, he said he is surprised that the CTA is only now discovering that its trains require a longer stopping distance than previously thought.
The CTA specified that the train should be able to stop in 1,780 feet, but the NTSB found it needed 2,745 feet to stop. The CTA used typical stopping distances for older-model L trains that don’t reflect newer, heavier L cars, Homendy said.
From investigating the accident, the CTA may learn about residue hazards on the tracks, Schwieterman said. Just as buses and cars operating during rain require longer distances to stop, train operators should also take slippery tracks into account.
The CTA may also have to reevaluate the use of work equipment during daytime hours because it increases the risk to commuters, Schwieterman said.
Helmer’s daughter, Margaret Costello, who was also on the train with her 2-year-old twins, said she was upset that the CTA had not implemented an automatic braking system recommended by the NTSB more than a decade ago.
“It looked like something that was going to happen, and yet it was allowed to happen,” Costello said.
The NTSB recommended positive train control for all rail systems nationwide in 2009.
Positive train control can track every train running on the tracks. It is designed to automatically stop a train if an operator runs a signal or slow it down if it is moving too fast.
The agency advised the CTA installed the technology in 2014 after a Blue Line train crashed into the O’Hare International Airport terminal. But the CTA was not required to install the technology because it is exempt from the kind of federal oversight given to Metra and Amtrak.
The CTA did not respond to detailed questions about the incident for this story.
“The CTA continues to work closely with the NTSB in their investigation,” the transit agency said in a statement. “We will continue to cooperate fully with the NTSB in its investigation process, which is ongoing. As the chairman of the NTSB said yesterday, there are no safety issues with taking the train.”
The NTSB did not immediately respond to a request for comment.
Alishan Zaidi, who was in the lead car that crashed, said he believed the theory that the train’s wheels lost traction on slippery tracks.
After the train crashed, he said he saw the driver unfreeze and say the brakes failed to stop the train.
“He said he should have stopped but he didn’t,” Zaidi said.
Zaidi, 19, of Des Plaines, a DePaul health sciences student, recalls a gap of two or three seconds between the time the brakes were applied and the time the collision occurred.
“I heard the brake being pulled, then I heard the screech of the brake being pulled hard. I said, “That was weird, I had never heard that before.” Everyone was in shock,” she said.
Zaidi is more cautious about riding L trains since the accident. He would try another method of travel, but he says, “I don’t have much choice.”
The afternoon after the accident, he had to take a Red Line train back north from the school center. That time, she said, she chose a central train car and prepared her body in case of another sudden stop.
“I was uncomfortable with the noises I heard,” he said. “You hear the screeching normally, but I still prepared myself.”
The Yellow Line service remains suspended.
Contribution: Rosemary Sobol