2008 Massachusetts train collision
On May 28, 2008, shortly before 6 p.m., two westbound trains on the MBTA Green Line D branch collided between the Woodland and Waban stations in Newton, Massachusetts. Early findings indicated that the operator might have been distracted by texting; however, the National Transportation Safety Board (NTSB) later determined that the operator of the trailing train, Terrese Edmonds, suffered a micro-sleep episode linked to sleep apnea, which caused a lapse in situational awareness. The collision resulted in Edmonds' death and injuries to fourteen passengers, one of whom required air evacuation to a medical facility. This accident, along with a similar event the following year, led the NTSB to implement more stringent restrictions on cell phone usage for train operators.
Background
The Green Line is a light rail network managed by the Massachusetts Bay Transportation Authority (MBTA) serving the Boston metropolitan area. It holds the distinction of being the oldest subway system in the United States. The Green Line branches into several routes; among them, the D branch operates as a grade-separated double-track line running from Riverside to Kenmore stations. At Kenmore, it converges with other branches onto shared tracks heading into downtown Boston. Between Waban and Woodland stations, the D branch utilizes automatic block signaling. According to operational protocols, trains encountering a single red signal must stop for one minute before proceeding at a restricted speed not exceeding 10 mph, remaining prepared to halt if an obstruction is detected.
Accident
The 2008 collision took place on the westbound track segment between Waban and Woodland stations involving two Green Line D branch trains numbered 3667 and 3681. Around 5:50 PM, Train 3681 departed from Waban station, passed signal H-64 which showed a single red aspect indicating Train 3681 was ahead, then stopped at signal H-66. Following established procedures, it waited one minute before moving past H-66 at a restricted speed, reaching approximately 3.4 mph at the moment of impact.
Train 3667 left Waban trailing Train 3681. Despite signal H-64 displaying red, which mandated a stop and hold, an MBTA staff member reported that Train 3667 did not reduce speed upon departure and accelerated to its maximum authorized velocity of 40 mph. Traveling at about 38 mph, Train 3667 struck the rear of Train 3681, severely damaging its lead car and crushing the operator’s cab. The operator of Train 3667, Terrese Edmonds, died from blunt force trauma sustained in the crash; eight passengers sustained injuries.
Investigation
At first, investigators attributed the incident to operator error and considered that Edmonds might have been distracted by using a cell phone while driving the train. However, after examining relevant records, the NTSB ruled out cell phone use as a factor. The investigation confirmed that train brakes had not been applied and that there were no track defects.
The NTSB ultimately determined that Edmonds likely experienced a micro-sleep episode caused by sleep apnea which led to a loss of awareness. Edmonds was relatively new to train operation and had met only minimal qualification requirements including holding a high school diploma, possessing a valid driver’s license, passing a background check, and completing seven weeks of training.
Aftermath
The NTSB issued its conclusive report on the accident in 2009. Approximately one year later, a separate event occurring on the identical route was attributed to an operator engaging in texting while driving.
See also
Other comparable incidents
- 2016 Hoboken train crash, where the engineer was found to have sleep apnea
- 2016 Croydon tram derailment, a light rail accident caused by the driver’s sleep apnea
- Bourne End rail crash, a postwar UK accident possibly linked to sleep-related distraction
- December 2013 Spuyten Duyvil derailment, where the engineer’s sleep apnea contributed to inattention
- June 2009 Washington Metro train collision, a rear-end crash involving high-speed impact and telescoping train cars