Credit: Photo courtesy of Purple Line Transit Partners

This story was updated at 4:03 p.m. on April 27, 2021, to include additional information

Maryland has rejected a proposal by Montgomery County Executive Marc Elrich to single-track the Purple Line in downtown Bethesda.

Elrich asked the state to consider single-tracking the future light rail line, which will connect Bethesda and New Carrollton in Prince George’s County. He has said the plan would save the county about $54 million of construction for a second tunnel to run parallel to the Purple Line and house the Capital Crescent Trail.

The plan for the 16-mile line has been to have two tracks running into an existing tunnel that would lead into the Bethesda station, which is to be the line’s western terminus.

A new separate tunnel for the trail is in the six-year capital budget as part of the construction of the trail. Funding it has been a point of contention between Elrich and the County Council for the last two years.

Maryland Secretary of Transportation Greg Slater wrote in a letter on Monday to Elrich, Montgomery County Transportation Director Chris Conklin, The County Council others that the state Department of Transportation and Maryland Transit Administration were “unable to accommodate the single-tracking option.”


Slater wrote in the letter that for the single-tracking proposal to go forward, the Federal Transit Administration would need to approve.

“Our federal partners are not in favor of a change that diminishes operational capacity and flexibility, and discussions have touched on several regulatory and funding risks associated with the proposed reconfiguration,” he wrote.

Slater wrote that there are physical challenges related to aligning the trail and the Purple Line in the same tunnel, such as the gantry system — a structure that supports the overhead catenary that delivers electric power to the trains. Additionally, the single-track proposal could mean that the station platform would have to be single-sided instead of double-sided, and it might need to be lengthened to accommodate more passengers.


Some County Council members have been critical of the single-track proposal out of concern that it could lead to longer headways between trains. But Elrich has said he doesn’t think headways would be affected.

Elrich told Bethesda Beat in March that under his proposal, one track would run from the station through the tunnel before dividing into two tracks. He thought that eight-minute headways would be enough time for trains to enter the station, pick up and drop off passengers, and pull back out in a timely manner.

Elrich could not immediately be reached for comment on Tuesday.


Slater wrote in his letter on Monday that state officials estimate that trains will spend six minutes in the Bethesda station, which includes time for passengers to board and detrain, the operator to switch ends and to clean up trash.

Eight minutes, he wrote, would be the minimum amount of time trains could get in and out of the station due to “the need for trains to wait to traverse the single-track section.”

Slater went on to write that short-term cost savings in the county’s capital budget would be “negated” later by “numerous down-stream expenses.”


As an alternative for helping the county save money on the Capital Crescent Trail tunnel, Slater noted that there are many state and federal grants and loans available.

Council Member Evan Glass, a member of the Council’s Transportation and Environment Committee, wrote in a statement on Tuesday that he is pleased the state supports keeping the two-track tunnel for the Purple Line.

“Retaining this best-practice design will allow trains to run more frequently and prevent unnecessary bottlenecks along the route,” he wrote. “The Council has funded a design and construction timeline for a tunnel to carry the Capital Crescent Trail so that both trains and trail users have a high-quality facility that properly accommodates the multi-modal transportation options that make Bethesda a success.”


Dan Schere can be reached at