Metro Investigators have determined that a so-called "heat kink" was the "probable cause" of a derailment that snarled mass transit during Friday's rush hour.
Three cars of a southbound Green Line train derailed at approximately 4:45 Friday afternoon as the train was entering a tunnel from an outdoor section of the tracks near the West Hyattsville station.
No injuries were reported as a result of the derailment, but 55 passengers were evacuated and a pregnant woman was taken to the hospital for observation.
"Heat kinks are short sections of misaligned track caused by the expansion of metal rails in extremely high temperatures and prolonged exposure to direct sunlight," Metro's statement explained. "When the expanding rail cannot be constrained by cross-ties and ballast, the rail may expand outward from the normal track alignment."
As a result of the derailment, all scheduled track work on Metro was canceled for the weekend, while trains operated on a speed limit of 35 miles per hour. Green Line service between Fort Totten and Prince George's Plaza remained suspended Saturday as crews worked to re-rail the cars and repair damaged track, third rail, and fasteners.
The "heat kink" in the tracks near West Hyattsville station. Photo Courtesy Metro.
Below, video taken from inside the train. Courtesy: The Gazette