From Washington Union Station Amtrak train to Baltimore then Amtrak Thruway to Ocean City, MD. 4 h 36 min. From ARCHIVES station subway to Greenbelt Metro Dr & Cherrywood La, bus to BWI-Thurgood Marshall Airport, then shuttle to Ocean City, MD. 5 h 32 min $116. From Washington drive to Ocean City. 2 h 57 min $16.