WASHINGTON, DC (WUSA)-- Metro officials say that investigators have determined that a misalignment of the rails, known as a "heat kink," was a probable cause of Friday's derailment near West Hyattsville Station.
A Metro spokesperson said that three cars of an inbound Green Line train derailed at approximately 4:45 p.m. as the train entered a tunnel from an outdoor section of track. There were no injuries.
Metro explained that 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. When the expanding rail cannot be constrained by cross-ties and ballast, the rail may expand outward from the normal track alignment.
Metro officials say that investigators are working to identify any contributing factors.
Green Line service between Fort Totten and Prince George's Plaza will remain suspended throughout the day Saturday as Metro crews work to re-rail the derailed cars and repair damaged track, third rail and fasteners in the area of the incident.
Metro has canceled track work on all other lines for the weekend and trains will travel at 35 mph.