The former tunnel underneath Wisconsin Avenue that connected the Georgetown Branch Trail with the Capital Crescent Trail at Bethesda Row is now closed due to Purple Line construction Credit: Rails to Trails Conservancy/ Barry Ladwig

Montgomery County officials have developed three options as they work on the design of a new Capital Crescent Trail tunnel to be built underneath Wisconsin Avenue in Bethesda.

The county is developing designs for the tunnel because the Purple Line will require most of the space in the existing tunnel that had encompassed the trail underneath the Carr Properties project and Air Rights Building on either side of Wisconsin Avenue. The section of the trail that ran through the tunnel was closed last year as construction on the light-rail line got underway.

The new tunnel would provide a direct route underneath the busy downtown road so cyclists and pedestrians would not have to cross Wisconsin Avenue. The three design options have differences—one has the tunnel emerging on Elm Street, another in Elm Street Park and the third next to Elm Street Park, according to the preliminary drawings.

On Tuesday, Glenn Orlin, the County Council’s deputy director, told the council that the Department of Transportation is reviewing the three options and updating their designs. The department plans to present its recommendations on the project to the council in about a year and a half. The county has budgeted $3.8 million to design the tunnel and estimates the project would cost $15 million to $25 million to construct.

Orlin told the council the design should be finished in time for the council next year to set aside the construction funds that would allow the tunnel to be built by the scheduled opening of the 16.2-mile line in 2022.

The tunnel has been a point of controversy as construction of the Purple Line ramps up in the area. In early 2017, Planning Board Chair Casey Anderson said he was dismayed by the lack of progress on the tunnel at that time—noting then that little planning work had been completed.


The council later approved the design funding for the tunnel in March 2017.

The county also has developed the design of the surface trail that runs along Bethesda Avenue and across Wisconsin Avenue as well as along Willow Lane and 47th Street in Chevy Chase. This surface trail will connect the existing Capital Crescent Trail at Bethesda Row to the Elm Street Park area where it will rejoin the new segment of trail being constructed next to the Purple Line.


A Planning Board map showing the surface trail alignment and the currently unfunded tunnel route underneath Elm Street. Both the tunnel and the surface trail will connect with the main trail segment near Elm Street Park in the Town of Chevy Chase once completed.

The extended Capital Crescent Trail will replace the Georgetown Branch Trail, the unpaved trail between Silver Spring and Bethesda that closed last year to make way for Purple Line construction. The light-rail line will travel on the former trail’s route and the new transit system will have stations in downtown Bethesda, on Connecticut Avenue and in Lyttonsville as well as one next to 16th Street and two in downtown Silver Spring—at the transit center and the Silver Spring Library.

The county has budgeted about $61.2 million so Purple Line Transit Partners, the private construction team building the light-rail line, can build the new portion of the trail that will stretch from downtown Bethesda to downtown Silver Spring.


There has been no change in the projected cost of the new trail or the schedule of payments the county is making to the state so it can pay Purple Line Transit Partners to construct the trail, according to council staff.

CCT Tunnel Option #1 Elm St Portal_Plan


CCT Tunnel Option #2 Elm St Park Portal_Plan

CCT Tunnel Option #3 Under Elm St Park_Plan 


Tunnel design PDFs provided by Montgomery County

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