On December 1, 2013, a Metro-North train was speeding around a sharp curve on its tracks when it derailed. The train crash killed 4 and injured 115. According to federal investigators, the engineer conducting the train suffered from undiagnosed severe obstructive sleep apnea. I was on my way to work when I heard about the crash. It wasn’t the first like it. It wouldn’t be the last. A May 2013 freight train collision and, more recently, a train crash at O’Hare International airport underscore why this important issue warrants our attention.
Metro North train crash report
A medical report made public by the National Transportation Safety Board (NTSB) regarding the Bronx train crash disclosed that the sleep apnea diagnoses of Mr. William Rockefeller, the train’s engineer, was not known at the time of the accident. He nodded off and entered a “hypnotic-like daze.” Before the train derailed, he tried to slam on the brakes. Unfortunately, this was too little and too late to avoid catastrophe. The lack of screening to detect sleep apnea undoubtedly contributed to the derailment. The hypnotic “daze” described by the engineer may have been an episode of microsleep. These episodes are often described as “spacing out” and associated with sleep apnea and sleep deprivation.
Other Train collisions
If train crashes were rare, or if other collisions were not related to sleep, this might not be as alarming. Unfortunately, they are not rare. Recent evidence shows an increased recognition that sleep disorders contribute to many train crashes. A review of reports issued in 2014 by the NTSB revealed 14 collisions or derailments. Twelve reports, included a probable cause. Three of twelve or 25% of these reports were related to sleep, with two specifically mentioning sleep apnea.
- On May 25, 2013, two commercial freight trains collided near a train crossing at Chaffee, Missouri at around 2:30 AM. Two locomotive engines and 13 cars derailed at the site. Both the engineer and conductor were injured. The NTSB investigation concluded that engineer fatigue due to undiagnosed sleep apnea was responsible.
- On March 24, 2014, around 2:49 AM the Blue Line train at O’Hare International Airport Station failed to stop when it approached the station. It collided with a bumper post. The lead car derailed and “rode” an escalator (see video) frequented by the public at the airport terminal. The train crash injured 33 individuals including the train engineer. The operator of the train had fallen asleep when the train arrived at the station. Had the event taken place during peak hours, possibly hundreds of individuals would have been near the platform and escalators when the train came crashing through it.
Preventing another train crash
Undiagnosed sleep apnea threatens more than just individuals who have sleep apnea. These individuals conduct trains and planes, and operate devices that require sustained attention. The NTSB have made recommendations that individuals in such positions undergo screening for sleep disorders. This appears to be a prudent recommendation given the history of train derailments and collisions such as the Metro North train crash and the incidents at O’Hare International airport among other incidents.
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