Metro is proposing to fix water leaks in a section of Red Line tunnel between Friendship Heights and Grosvenor stations that would result in closing the Bethesda, Medical Center and Grosvenor stations for 14 weeks sometime in the summer or fall of 2016.
Metro detailed the work in documents as part of a presentation to its board scheduled for Thursday.
In the report, the transit operator said tunnel leaks in this section have caused one third of the system’s incidents of arcing insulators, resulting in sparks and fires stemming from the third rail and leading to service disruptions.
“Since Metro opened the Bethesda and Medical Center stations in 1984, water infiltration in this section of the Red Line has caused disruptions and has required extensive maintenance over the years to control it,” Metro said in its presentation report. “The tunnel requires ongoing pumping, dredging and cleaning to keep switches in service and to prevent arcing insulators.”
To fix the leaks, Metro is proposing to install a drainage system and new precast concrete arch inside the tunnel with waterproofing. Metro estimates the cost will be $12.2 million.
Metro says it also will begin work during the weekend closures to prepare the Bethesda station for the construction of a new station that would accommodate the light-rail Purple Line. It’s proposing to open a side of the existing station to connect the Purple Line station entrance as well as install elevators, electrical panels, lighting and architectural finishes.