A loose part under a Metro train, which struck a power cable, seems to have been the cause of a fire during Tuesday's evening rush hour that frightened passengers and led to a rough commute home for many.
As a result, Metro will re-inspect its oldest rail cars. The car involved in Tuesday's incident was a 1000-series train, among the oldest in the fleet.
The new 7000-series rail cars will replace the 1000-series next year.
No 1000-series trains will be taken out of service, but the transit agency wants to make sure that no other trains have loose parts. Track conditions were not a contributing factor to the Tuesday fire, Metro says.
According to a preliminary investigation, it's possible the train's metal-shielded hoses came into contact with power cables under the car's body, creating an electrical short.
But a definitive cause has not been determined. Officials say their investigation will take several days to complete.
The fire led to the suspension of service between Takoma and Forest Glen during rush hour Tuesday evening.
The flames under the train car were visible on security camera footage from the Silver Spring transit center and on passengers' cell phone video.
The passengers on the train were evacuated at Takoma Park station, before the flames were seen.
But some witnesses nearby reported that they heard three loud booms from the train.
"Very loud," said witness Dorsey Evans. "And then all of a sudden I saw the flames coming from underneath the Metro car."
Service between Takoma and Forest Glen was restored by 7:30 p.m. Tuesday, but access to the Silver Spring station was limited, with passengers allowed only to exit at the station, for almost two more hours.
"You never know what you can expect with the Red Line," one passenger said.
"Not entirely happy with Metro," said passenger Sean Griffin. "I got charged for the experience of not getting where I was going, so that did not make me happy."
The fire did not spread inside any railcars, and firefighters extinguished the fire with a dry chemical.
Metro officials did not tell News4 how often fires happen on trains, tracks or in stations. But News4 has reported on at least 10 incidents of smoke or fire on Metro trains or tracks, reported Shomari Stone.
"I would say incidents like tonight's are extremely rare," said Caroline Lukas, of Metro.