Metro is advising customers of evening and weekend service changes on the Red Line starting Friday, December 22, and continuing through Thursday, February 15, in order to extend a water leak-mitigation project and improve reliability.
The pilot, which began in July, is using a new waterproofing technique to reduce water infiltration in the Red Line’s deep tunnel segments that are prone to leaks. The pilot was expanded in October following early results that showed improvement in keeping the tunnels dry.
During the project, trains will single track during the evening and late night hours on weeknights, in addition to weekends, to allow Metro and its contractors to install a new waterproof membrane using a “curtain grouting” technique that requires drilling hundreds of holes through the tunnel ceiling and injecting a proprietary polymer-based material through the holes to form a protective layer on the exterior of the tunnel walls.
The leak mitigation pilot began with two test segments – a 2,000 foot section of inbound track between Medical Center and Bethesda and the entire Medical Center interlocking. A third test segment tripled the size of the initial pilot – with an additional 4,000 foot-section of inbound track between Medical Center and Grosvenor.
The deep tunnel segments on the Red Line between Dupont Circle and Grosvenor are well below the water table and were built before the widespread use of NATM, the New Austrian Tunneling method, which provides a tunnel with a waterproof membrane. As such, the tunnels are subject to water infiltration from the high hydrostatic pressure that can cause track infrastructure to more quickly corrode.
Due to the extensive length of the tunnel segment the project is expected to take eight weeks (including 9 weekends) to complete the work. During this time Metro will implement the following service changes:
Red Line trains will single track as follows:
Medical Center – Grosvenor
December 26-28, January 2-4, 8-11 9 p.m. through closing nightly
December 22-24 6 p.m. Friday through closing Sunday
December 29-31 9 p.m. Friday through 6 p.m. Sunday
Friendship Heights – Grosvenor
Weeknights (Mon – Thurs)
January 16-18, 22-25 9 p.m. through closing nightly
January 13-15 7 a.m. Saturday through closing Monday
January 20-21 7 a.m. Saturday through closing Sunday
Friendship Heights – Medical Center
January 29-February 1, 5-8 and 12-15 9 p.m. through closing nightly
January 27-28, February 3-4 and 10-11 7 a.m. Saturday through closing Sunday
At this time the work involves single tracking only. Metro will update customers if there are any changes to the service plan.