MARC at Monocacy Junction. The Frederick Branch of the Baltimore and Ohio Railroad was built in 1831 off of what was then the main line, presently the Old Main Line Sub. Eventually it would join the B&O with the Pennsylvania Railroad and the Hagerstown & Frederick, while providing both passenger and freight service. In 1949, passenger service was abandoned. In 1987, the State of Maryland purchased the branch, and returned passenger service to 2 newly contructed stations on the line in 2001. By the time this photo of Maryland Transit Administration/MARC Train 893 with MARC 34 (MP36PH-3C, MPI) was taken on June 23, 2021, CSX had no customers left on the branch. This leaves MARC's 3 scheduled trains between Washington D.C. and Frederick, Maryland as the sole traffic, but Train 893 was the only one operating during the pandemic related reductions. The other legs of this wye, which sits inside of Monocacy National Battlefield, continue as the Old Main Line Sub between Relay and Point Of Rocks, Maryland.
From B&O RDCs to MARC bilevel coaches pulled by electric locomotives and diesels, the Maryland commuting scene has evolved, while trolleys, aka light rail vehicles, are back.