NTSB Yellow Line crash report finds CTA disabled a braking feature, contributing to collision

Yahoo

12-02-2025

A federal investigation into a CTA Yellow Line crash has found the transit agency disabled one automatic braking feature on the popular model of railcar involved, contributing to the 2023 collision.
The National Transportation Safety Board's final report on the crash, dated the end of January, determined other factors also contributed to the crash, including the need to suddenly slow the train from the speed limit of 55 miles per hour to a complete stop. So did the presence of crushed leaves and plants, which made the rails slippery and likely worsened sliding of the train wheels, the NTSB found.
Earlier in the investigation the NTSB found the operator of the train had alcohol in his system after the crash, violating federal rules, though federal officials said at the time they did not believe the operator's action contributed to the crash. In the final report the NTSB again reiterated the operator responded quickly to a signal command to stop the train and determined, 'It is unlikely that effects of ethanol contributed to the collision.'
The operator remains on leave from the CTA, and the agency has not made a final determination about the status of his employment.
The report comes more than a year after the Nov. 16, 2023, crash, and marks the completion of the NTSB's investigation. A train on the Yellow Line, also known as the Skokie Swift, hit a snowplow that was on the tracks for scheduled training, injuring some two dozen passengers and CTA employees including the train operator.
The crash caused an estimated $8.7 million in damages, and left the train line closed for seven weeks as the CTA worked to ensure the safety of the trains that carry commuters between Chicago's Rogers Park neighborhood and Skokie.
The operator, approaching the Howard station on his third trip from Skokie that day, received a command from CTA's signal system to stop the train because of an object on the tracks ahead. The operator applied brakes one second later, and when he saw the snowplow ahead of him he hit the emergency brakes, the NTSB found. But, under the 'aggressive braking' required to suddenly stop the train the railcars slid, and the train slowed only to 23 miles per hour before it slammed into the snowplow.
The crash involved 5000-series train cars, which is the CTA's most common model. The cars have three types of brakes, and when the system designed to prevent the wheels from sliding kicked in, two types of brakes were automatically activated but not the third. The CTA had deactivated the third type of brake from automatically kicking in during wheel slides on such train models during testing in 2009, the NTSB determined.
At the time, the CTA determined the wheel-slide protection system tended to continuously use the third type of brake, which could cause frequent braking and discomfort for passengers. The decision left the use of the third type of brake up to the operator, the NTSB said.
'If the wheel slide protection system had been set to automatically apply the (third type of) track brakes when wheel slide was first detected, the train likely would have decelerated more quickly, reducing the severity of the accident or preventing the collision altogether,' the NTSB found.
The CTA had inspected the tracks the day of the crash without finding 'defects or unusual conditions,' the NTSB report noted. But the federal agency also said the CTA's inspections before the crash did not include checking for leaves or material buildup and the CTA did not clean the rails and did not apply sand.
'If CTA had cleaned the rails or taken steps to increase rail adhesion, the train's wheel slide would have been less pronounced, likely preventing or reducing the severity of the collision,' the NTSB report said.
Since the crash, the CTA lowered maximum speeds on the Yellow Line from 55 miles per hour to 35 to limit the possibility of having to suddenly bring a train to a complete stop from the higher speed, and reconfigured its system to get rid of all places where a train might have to suddenly stop from 55 miles per hour. The agency enabled the automatic use of the third type of brake on 5000-series railcars, the NTSB said, and cleaned the Yellow Line rails.
The agency also issued reminders to employees on best practices for operating trains when tracks are slippery, and changed its track inspector training to include information about buildup on rails, according to the NTSB.
The CTA described measures it took after the crash as 'proactive and precautionary.'
'Throughout the course of the NTSB investigation, which is now complete, the CTA was fully cooperative and assisted federal investigators, while also conducting its own testing of equipment and procedures,' agency officials said in a statement. 'While the investigation was ongoing, CTA pre-emptively implemented several new measures for added safety along the Yellow Line which have already addressed the contributing factors outlined in the final NTSB brief.'
Early in the investigation, NTSB Chair Jennifer Homendy said the agency was investigating the train line's 1970s-era signal system, which controls how trains move and the distance in which they stop. The NTSB was also investigating braking systems, residue from organic material on the tracks — such as leaves — and other factors, she previously said.
In the final report, the NTSB determined that under ideal conditions the train could stop within the distance designed by the signal system, which was 1,780 feet. But investigators could not replicate the conditions during the crash, which were not ideal.
Braking on the train began farther out than the 1,780 feet intended for ideal conditions.
Nearly a decade before the Yellow Line crash, the NTSB investigated a 2014 crash in which a Blue Line train pulling into the O'Hare International Airport station crashed through a barrier at the end of the tracks and landed on top of an escalator.
The NTSB recommended after that collision that the CTA install a more robust type of train control system. Among the changes included with that more robust type of control is stopping a train before it passes a signal, while the CTA's current system kicks in once a train passes a signal, Homendy has previously said.
The Federal Transit Administration has not mandated that public transit systems adopt the more robust type of train control system, and the CTA has previously estimated it would cost nearly $2.5 billion.
The NTSB did not issue safety recommendations for the CTA as a result of the Yellow Line crash.