Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Brunswick Line is a MARC commuter rail line consisting of a main line running from Washington D.C. to Martinsburg, West Virginia and a branch line from just south of Point-of-Rocks station to Frederick, Maryland. The service is operated under contract by CSX Transportation, but is administered by MARC, a service of the Maryland Transit Administration. The Brunswick Line is MARC's longest line, and operates over CSX's Metropolitan, Old Main Line, and Cumberland Subdivisions.