Metro’s planning staff in 2013 proposed creating a second Rosslyn Tunnel to exclusively serve the Blue Line. Since then, there hasn’t been much progress. (WMATA)

Metro officials are taking a small but symbolic step in their hope of someday building a second station in Rosslyn.

On Thursday, the Metro board is expected to approve an application to the Northern Virginia Transportation Authority to request $2 million in grant money that would help the agency study ways to increase capacity on the Blue, Orange and Silver lines in Northern Virginia.

Metro’s big idea? Build another station in Rosslyn, with its own separate tunnel to the District, then separate the Blue Line from the Orange and Silver lines. That second Rosslyn terminal would be connected to the original Rosslyn station with some kind of underground pathway, allowing riders to travel between the two. Such a project would help alleviate the congestion inside the Rosslyn tunnel, a well-known bottleneck in the Metro system, and it could eventually better connect Northern Virginia with Georgetown.

It could also cost billions of dollars.

The idea for a “Rosslyn II” station received significant attention in 2013 when Metro’s planning staff released a “Proposed 2040 Metrorail Network” that would expand train capacity through downtown Washington and Northern Virginia.

By separating the Blue Line from the Orange and Silver lines and adding extra tracks through the core of the District, Metro could “reduce future crowding on Metrorail, provide enough capacity for future development, and expand the reach of transit in the region, especially to regional activity centers,” according to the December 2013 Plan It Metro blog post.

Now, four years later, the region isn’t much closer to making that dream map a reality by 2040.

The Metro board vote Thursday doesn’t do much to significantly advance the project. If Metro ultimately obtains funding from Northern Virginia to conduct a study, the transit agency would be able to get a potential estimate on the construction costs and a more comprehensive sense of the potential benefits and drawbacks of the project. They also would assess other potential strategies for increasing capacity on the Blue, Orange and Silver lines in Northern Virginia.

“This funding would begin the process to address capacity issues at Rosslyn station as well as reliability issues throughout the corridor,” Metro officials said in their summary to the board. In addition to applying for a grant for research on the Rosslyn II station, Metro also plans to ask the transportation authority for $94.7 million to help fund more upgrades to the transit system’s track power and communications systems, a project that is ongoing and is meant to help it ultimately be able to run eight-car trains exclusively.

Even though the study doesn’t do much to nail down funds for such an ambitious project or lock in necessary support from regional leaders, it’s a sign Metro officials remain interested in thinking about expanding the capacity of the system and preparing for future growth … even as the transit agency continues to battle to hang on to the riders it has.