A westbound MARC train passes through the settlement of Boyds, Maryland on the former Baltimore & Ohio Metropolitan Subdivision. Both of these locomotives plied these rails as B&O road units in the past. CSX GP40 6594 was once B&O 4019, and MARC 8100 was once B&O F7A 4553. The GP40 is providing the tractive effort, as the bulldog is now capable of providing HEP only.