The Penn Line is a commuter rail service operated by MARC (Maryland Area Regional Commuter) that connects Washington, D.C. to Baltimore, Maryland. It primarily serves passengers traveling between these two major cities, making stops at various stations along the way. The line is known for its convenience and efficiency, catering to daily commuters and occasional travelers alike. Trains on the Penn Line run frequently during peak hours, providing a reliable option for those looking to avoid traffic. The service is part of the larger MTA Maryland system, which aims to enhance public transportation in the region.