After two and a half years of planning and more than 100 tested proposals, Metro has settled on a map it hopes represents the future of the system. The map, which Metro planners expect to bring before the Washington Metropolitan Transit Authority board next year as part of the long-term regional transit plan aimed at the year 2040, centers on a new “loop” line encircling downtown D.C. that would provide new connections, bring Metro stations to high-demand areas, and ease overcrowding in the city core.

The concept, published yesterday on WMATA’s PlanItMetro blog, hinges on the separation of the Blue and Yellow lines from their Orange and Green companions in order to create the loop, which would run in both the clockwise and counterclockwise directions. The proposal would create new Metro stops at Georgetown University, Georgetown, West End, Thomas Circle, Mount Vernon Triangle, Capitol North, and Potomac Park. It would also establish an express line from Georgetown/Rosslyn to Ballston, bypassing the majority of Arlington for the benefit of Virginia commuters to downtown D.C.

“It connects all of the regions downtown,” says Metro planning director Shyam Kannan. “When the system was built, we had one downtown.” Now, he says, areas like NoMa, Rossyln, and the east end of downtown have flourishing commercial markets and need better connections.

Additionally, splitting the paired lines allows for more frequent trains along the Green Line, where people traveling to the Capitol Riverfront for a meeting at the Department of Transportation have to wait up to 12 minutes for a train; two separate lines can each run more often. “We don’t want to be caught with our pants down 20 years from now when the Green Line is popping and we weren’t prepared for it,” Kannan says.

Two months ago, PlanItMetro presented its four leading concepts for new downtown lines. Three of those scenarios involved a new line along 10th Street NW/SW, where the National Capitol Planning Commission envisions redevelopment to create a major retail corridor. But according to Kannan, even with new development and a hypothetical repeal of the Height Act, there wouldn’t be enough density around 10th Street—-given the presence of existing lines along 7th and 12th streets—-to justify the new line.

The current proposal has the distinct advantage of creating a new line through Union Station, which is already the station where the most people enter the Metro system and will only become more crowded when the planned redevelopment of the station allows for more Amtrak and commuter-line traffic. “Union Station really is the region’s fourth airport,” says Kannan. The proposal would also make it much easier to move between Metro lines, with new transfer stations at Farragut Square, Capitol South, Navy Yard, Waterfront, and of course Union Station.

Kannan says that versions of the proposal have already received broad support from community stakeholders: Georgetown residents who want Metro access, Capitol Riverfront business people who want more frequent service, the developer Akridge, which is overhauling Union Station and wants more connections to the Metro system.

One area of potential conflict: The proposed Metro line largely parallels the planned streetcar route from Union Station to Georgetown. But Kannan says the two systems will serve different functions and shouldn’t conflict, given that Metro is designed for long commutes where the streetcar isn’t practical. “They’re different markets,” he says. “Streetcar’s a last-mile solution.”

Unlike the mess of jackhammering and digging that pestered businesses and residents when the initial Metro system was built, Kannan says there’ll be “minimal to negligible disruption” this time around due to improved technology that allows for underground tunnel boring rather than digging from the street level. “The days of cut and cover are gone,” he says.

Metro is still working out the specifics of the plan, down to details like whether the new Metro tunnels will run below the existing ones and how they’ll connect. According to Kannan, those details will be included in an implementation plan that will be completed around the middle of next year.

Map from PlanItMetro