馬里蘭區域通勤鐵路
Current MARC Train service includes the Penn Line (operated on Amtrak's Northeast Corridor), the Camden Line (operated on CSX's Capital Subdivision), and the Brunswick Line (operated on CSX's Cumberland, Metropolitan, and Old Main Line Subdivisions, with limited service along the Frederick Branch). There are 42 MARC Train stations in the commuter rail system; all three lines terminate at Union Station in Washington, D.C, where passengers can connect with Amtrak, Virginia Railway Express, and Washington Metro trains. Development of a new MARC station at the former Amtrak station in Elkton, Maryland began in 2014, with plans to open by 2040.