WASHINGTON — Metro riders were delayed by more track fires in the three months that ended Sep. 30 than the same period a year earlier.
The track fire trend in Metro’s latest quarterly safety report shows an increase from 15 reported fires in July, August and September 2014, to 19 in 2015, 28 in 2016 and 32 this year.
Over the last 12 months, arcing insulators are by far the most common problem. Documents prepared for the Metro Board arcing incidents doubled in the last three months over a year earlier, and blamed increased rainfall.
“The average amount of July rainfall in the area is 3.5 inches; this past July recorded over 9 inches of rain,” the board documents say.
Of the 19 incidents this quarter, nine were in July.
Arcing happens when electrical current jumps outside of its intended path, often due to water, dirt or grime buildup, or because of insulators that needed to be replaced. In July, August and September, the incidents were concentrated along the Red Line from Woodley Park through Medical Center and the Blue, Orange and Silver lines through Rosslyn.
Metro crews aim to clear out drains to limit water buildup, including crews who have been dedicated to clearing drains on part of the Red Line for months. The Federal Transit Administration said last year that unclogging all of the system’s drains would be the biggest single step Metro could take to resolve recurring track problems.
Metro is also “exploring alternative insulator designs that allow for more efficient insulator replacement.”
Other work intended to prevent some water from getting into the Red Line tunnel near Medical Center is proceeding in small pieces. The second phase of a pilot project includes a shutdown between Medical Center and Grosvenor this weekend.
Incidents of trash, leaves or other debris on the tracks catching fire dropped 39 percent over the last few months, to 11 during the period.
Two cable fires occurred: one involving a defective cable, another where a feeder cable was not properly connected to the electrified third rail.