The National Transportation Safety Board (NTSB) yesterday determined that operator fatigue caused a March 24, 2014 Chicago Transit Authority accident at O’Hare station which injured dozens of passengers.

Additionally, CTA did not effectively manage the operator’s work schedule to mitigate the risk of fatigue.

How it happened

The accident occurred at about 2:49 a.m. CST, when CTA train No. 141 collided with the bumping post at the end of the track. The train’s lead car rode over the bumping post and struck an escalator located at the end of the track, injuring 33 passengers and causing damage of more than $11 million. No one was on the escalator at the time of the accident.

12 days in a row

The operator had worked 12 consecutive days. During the accident trip, she fell asleep before the train entered the O’Hare station. She awakened when the train hit a safety feature called a track trip seconds before the train struck the bumping post.

“Managing operator fatigue is obviously crucial,” said NTSB Chairman Christopher A. Hart. “Transit agencies need to reduce the risk of fatigue in their scheduling practices, which CTA did not adequately do; and transit operators need to report to work rested, which this transit operator did not do.”

Before and after

Prior to the accident, CTA did not require fatigue awareness training for administrative managers whose responsibilities included scheduling regular and extra board employees. Additionally, there were no limits to the number of double shifts an operator could work, although operators were required to take off at least eight hours after working a double shift.

After the accident, CTA revised its work/rest policy. To ensure safer fatigue management in mass transit nationwide, the NTSB recommended that the Federal Transit Administration, which provides federal oversight for rail transit safety, develop a work scheduling program for rail transit agencies that reduces the risk of fatigue. The NTSB also recommended that the FTA establish hours of service regulations for mass transit operators, among other actions.

“We have seen again and again that local agencies take remedial action after an accident,” said Hart. “In mass transit, the FTA’s national oversight role allows it to ensure that the lessons learned through an accident in one city do not have to be re-learned through another accident in another city.”

Design flaws

The investigation also revealed a variety of design flaws in the placement of the station’s safety features, none of which applied the train’s brakes in time to stop it. Furthermore, the track that the accident train was traveling on at O’Hare station had a 25-mile-per-hour speed restriction, but the bumping post that the train struck was only designed to stop trains traveling at 15 miles per hour.

“In this accident, multiple redundant systems were intended to provide protection, but they were implemented in such a way that they never reduced the train’s speed,” said Hart. “But Transmission Based Train Control, a form of positive train control used in mass transit, would have prevented the accident.”

To view the full report, including the probable cause and all seven recommendations, click on the following link: http://www.ntsb.gov/news/events/Pages/2015_CTA_BMG.aspx