MARC Penn Line

Washington DC Union Station has tracks in a cut which is partially covered. There are 29 tracks. Tracks 16,17,18,19 have high platforms while the rest have 8 inch platforms. Access to the tracks is via ten "gates" but once inside the gates you could go to any track. Greyhound stops on the upper level and the WMATA Red Line stops on a lower level. Three MARC (Maryland Area Rail Commuter)  Lines stop here as does VRE (Virginia Railway Express).
 

New Carrollton, Maryland is also served by the WMATA Orange Line which has its own two tracks and high island platform to the south of the Amtrak/MARC station which has  four tracks, and a high island serving the inner tracks. The two outer tracks bypass the station.

Seabrook

Bowie State

Odenton

BWI Airport is being renovated and platforms lengthened. It has three tracks and two high side platforms. The center track bypasses the station. There is a crossover.

Halethorpe

West Baltimore

Baltimore Penn Station is a multi modal station with Amtrak, MARC and Baltimore's Light Rail. The light rail uses a low floor island  platform to the South of the Amtrak/MARC tracks. There are four high island platforms and eight tracks, tracks 6 and 7 being used for Amtrak. The station is in a partially covered open cut. Your webmaster thanks the anonymous gentlemen that answered questions about this station. Thank you, Gentlemen, for your contribution to this site.

Martin Airport

Edgewood has three tracks and two low 8 inch side platforms. The station's  South platform is over the abandoned fourth track.

Aberdeen has four tracks and two offset 0 inch side platforms

Perryville has 4 tracks and 1 low 0 inch platform on the North side