CHICAGO — Officials from the National Transportation Safety Board (NTSB) said a preliminary investigation has revealed that a design flaw was likely to blame for the crash involving a CTA train that left 38 people injured on Thursday morning.
During a press conference on Saturday afternoon, NTSB Chair Jennifer Homendy offered new details on the preliminary investigation into the crash which involved a snow fighter — a piece of rail-mounted snow-removal equipment that was on the tracks in the Howard Rail Yard, near the 7500 block of North Paulina Street.
NTSB officials said during the preliminary investigation, they reviewed the inward and outward-facing cameras in the train cab, the inward-facing cameras on the two cars and the train’s event recorder, a device that logs data about how the train controls were operated.
After reviewing the data, the NTSB said due to a design flaw in the CTA’s braking algorithm, the train failed to properly account for the actual distance needed to come to a stop.
As for the snow fighter, they said it was on the tracks because there were plans to train employees on it over the next few days.
Officials also found that there was a foreign substance on the tracks. NTSB officials said event recorder data showed that the wheels of the train did slip while it was braking, though it is unclear if the debris on the tracks played a role in the crash.
According to Homendy, train event recorder data revealed that the crash happened at 10:31 a.m. and that the train was traveling at a speed of 26.9 miles per hour when it struck the snow equipment. The train involved in the crash was designed to stop within 1,780 feet, but the NTSB said the train would have needed more space.
A brand-new system using the same track would require 2,745 feet to stop the train and, according to the NTSB, the 1,780 feet needed to stop is based on an old design and the recommended distance has changed over time due to several factors.
Six people in total were on board the snow fighter at the time of the crash, according to the NTSB. Officials say two people were on the back end, which was facing the train that crashed, and four were on the front end.
Since the crash, two lawsuits have been filed by men who were onboard the trains.
CTA Yellow line service was suspended on Friday and disruptions could continue as authorities investigate.
