According to an NTSB recommendation issued Friday, "unoccupied CTA trains are routinely left powered-up while stored" and with brake settings that "would allow movement through a mechanical train stop mechanism after a momentary stop."
The NTSB is urgently recommending that CTA officials install new redundant safety mechanisms called "derails" or "wheel chocks". Those mechanisms stop or derail a train if it runs away.
NTSB investigators believe if these safety measures were in place this week's crash could have been prevented.
The NTSB's urgent safety recommendations to the CTA include "reviewing operating and maintenance procedures for stored unoccupied cars" so that the trains are unable to run away.
NTSB investigators are still examining the cause of the accident but say they found that one of the cars on the unoccupied train had "thermally damaged wiring and water in electrical connection boxes on the car." Now, the CTA is checking the rest of the fleet of similar cars to see if they have the same problems.
The NTSB says they plan to complete their investigation on October 6 and then return to furlough as part of the ongoing government shutdown.
On Monday, 40 people were on a westbound train, which was stopped at the Harlem station, when it was struck by an eastbound train that was traveling on the wrong track around 7:45 a.m. Dozens of people were transported to hospitals, but all injuries were minor. The runaway train was parked at the Forest Park yard awaiting repairs. No one was inside the front car of a runaway train that struck another Blue Line train at the Harlem stop in Forest Park, CTA officials said after reviewing video.
As part of today's recommendations, NTSB officials also issued an urgent safety recommendation to the Federal Transit Administration directing them to issue a safety advisory to "all rail transit properties" in the country to make sure their unoccupied cars are stored property and are not in kept in a situation that would easily lead to runaway trains. The NTSB also recommended the nationwide installation of "redundant means of stopping unintended rail car movements."