From Metropolitan Branch Trail website:
The Metropolitan Branch Trail (MBT) is a proposed 8-mile multi-use trail that runs from Silver Spring in Maryland to Union Station in the District of Columbia. It also includes a segment that will connect the MBT at Fort Totten to the Anacostia Tributaries Trail System in West Hyattsville, Maryland, and a connection to the National Mall. The MBT will be an important transportation route providing direct access to seven Red Line Metro stations and connecting to the Washington area trail network at the Capital Crescent Trail and the East Coast Greenway.