The bizarre series of fires, smoke and power outages that stymied Metrorail travelers over a two-day period in August was caused by a failing transformer, a buildup of paper and flammable debris along the tracks, and a stray current that ignited the bolts that hold the tracks together, according to Metro’s final report on the events.
The report suggests taking preventive measures, such as installing infrared cameras throughout the system and replacing the stud bolts on the tracks, that would cost the transit agency $31 million, a Metro staffer will tell its board of directors today.
But officials still can’t explain why the events, which Metro Deputy General Manager Gerald Francis at the time called “unprecedented in our 31-year-history,” all happened at once.
“It took us a while to get to the bottom of this because there were so many things that occurred at the same time, and one thing compounds the other,” said David Couch, Metro’s managing director of engineering and capital projects.
Track fires at the Farragut North, Huntington and Pentagon City stations Aug. 26 and Aug. 27 were caused by stray currents, which ignited melting stud bolts, and by the accumulation of paper and debris, which caught fire as moving trains pushed them along the tracks, officials found.
Train power outages among the Pentagon City, Braddock Road, Ronald Reagan Washington National Airport and Pentagon stations were caused by a failure of one of the two power transformers at the PotomacYard substation.
A power surge from the dying transformer also caused a fire at the National Airport station communications room.
The 24-year-old transformers were due to be replaced this year, but were switched out early because of the incidents, Couch said.
To help prevent track fires, Metro is looking to tactics used abroad. The transit agency soon will place cages along the tracks to collect debris, as Toronto does, and is looking into placing infrared cameras throughout the system to detect stray currents, as is done in the London Underground.
