NTSB preliminary data shows design flaw in braking system of CTA Yellow Line train accident

Nov. 20, 2023
The accident injured 38 people when a Yellow Line train collided with a piece of snow equipment that was on the track for training.

The National Transportation Safety Board’s (NTSB) preliminary investigation has found a design flaw in the braking system of the Chicago Transit Authority (CTA) train that collided with snow equipment in an accident that injured 38 people, including six employees who were on the snow equipment. This is not a probable cause of the accident, only what initial data has shown.

An inbound Yellow Line train was approaching CTA’s Howard station when it collided with a diesel-powered snowfighter at 10:31 a.m. The train hit the piece of snow equipment at 29.9 mph, with NTSB stating it would take additional time to determine if the snowfighter had been stopped at the time of the collision or not. The piece of equipment was approved to be on the line as part of planned employee training ahead of winter. 

In a Nov. 17 media briefing, NTSB Chair Jennifer Homendy explained the investigative team onsite looked at the CTA’s signal system and preliminary determined it was functioning as it should. She also noted there was “thick and black” residue on the track and investigators had determined wheel slippage occurred during the braking of the train. Homendy noted additional analysis will determine if the residue came from debris, crushed leaves or another source. 

What Homendy reported the NTSB spent a good amount of time examining was the braking algorithm of the train. She reported the train was designed to stop at 1,780 feet when it should have had a braking distance of 2,745 feet.

“Our team was able to determine it was, in fact, a design problem,” said Homendy. “The braking distance should have been longer.”

She noted the investigative team will further examine why the train was using an old design and what changes to the system had occurred. 

While the investigation into the incident continues, CTA repeated its commitment to working with the NTSB.

“We reiterated and continue to demonstrate our pledge of full cooperation throughout the entire investigation and will provide the access to any information, facilities, equipment and personnel to the NTSB to ensure a thorough review,” said CTA President Dorval Carter, Jr.

About the Author

Mischa Wanek-Libman | Group Editorial Director

Mischa Wanek-Libman serves as editor in chief of Mass Transit magazine and group editorial director of the Infrastructure and Aviation Group at Endeavor Business Media. She is responsible for developing and maintaining the editorial direction of the group and is based in the western suburbs of Chicago.

Wanek-Libman has spent more than 20 years covering transportation issues including construction projects and engineering challenges for various commuter railroads and transit agencies. She has been recognized for editorial excellence through her individual work, as well as for collaborative content. 

She is an active member of the American Public Transportation Association's Marketing and Communications Committee and serves as a Board Observer on the National Railroad Construction and Maintenance Association (NRC) Board of Directors.  

She is a graduate of Drake University, where she earned a Bachelor of Arts degree in Journalism and Mass Communication with a major in magazine journalism and a minor in business management.