Map of the Purple Line route through Silver Spring and Langley Park. (Gene Thorp/The Washington Post)

Maryland officials and supporters of building a light-rail Purple Line through Montgomery and Prince George’s counties are drafting a “community compact” to define goals for economic development along the planned 16-mile corridor, including ways to preserve affordable housing, support small businesses and connect workers to jobs.

Supporters say the document, which will be crafted during two community workshops and modeled on similar agreements for transit projects in Seattle and Baltimore, will spell out a “livability strategy” for people in the proposed rail corridor between Bethesda in Montgomery County and New Carrollton in Prince George’s County. The light-rail line would have 21 stations, including in Chevy Chase Lake, Silver Spring, Langley Park, College Park and Riverdale Park.

Maryland transit officials and local government leaders have touted a new transit line’s ability to revitalize aging inner suburbs around stations as a key reason to build the light-rail project, now estimated to cost $2.43 billion to build and $58 million to operate annually. Much of the new development would be targeted in economically struggling areas of Prince George’s, such as Langley Park and Riverdale Park, officials have said, but Montgomery growth plans also call for more development in Chevy Chase Lake if a Purple Line is built.

Some community groups, particularly the immigrant advocacy group Casa de Maryland in Langley Park, have voiced concerns about redevelopment pricing out residents and businesses as rents increase and local residents benefiting from the project’s construction jobs.

A “Purple Line community compact” to address such concerns was proposed last year by the Fair Development Coalition, a group formed in 2010 by Casa de Maryland. The effort also is being led by the Purple Line Corridor Coalition, a group formed by the University of Maryland’s National Center For Smart Growth that includes community officials, nonprofit groups and businesses along the proposed route.

A compact is expected to be signed by the end of the year by state and county officials and the Purple Line Corridor Coalition, the group said. Cities, towns and community organizations along the route also will be asked to sign. The compact will be non-binding but will “state the intent” of those who sign it, the coalition said.

The first public workshop is scheduled for Oct. 25 from 9:30 a.m. to 12:30 p.m. at the Silver Spring Civic Building, One Veterans Plaza, in downtown Silver Spring.  The second is scheduled for Nov. 17, from 4 p.m. to 6 p.m., at Felegy Elementary School, 6110 Editors Park Drive, in Hyattsville.

A Purple Line is designed to connect Maryland’s Metrorail lines with Amtrak and commuter rail stations in a direct east-west route.  Supporters say it would spur redevelopment and provide faster, more reliable transit than buses. Opponents say it would destroy a popular wooded trail and threaten endangered species between Bethesda and Silver Spring, disrupt neighborhoods and be too expensive.

The project is pending federal construction aid and proposals due in January from teams of companies competing for a 35-year contract to design, build, operate and maintain the line, in addition to helping to finance its construction. State officials have said they hope to begin construction in mid-2015 and begin running two-car trains in 2020.