From Washington Union Station Amtrak train to Baltimore then Amtrak Thruway to Ocean City, MD. 4 h 36 min. From H St Nw & 16Th St X bus to UNION STATION MARC Washington, train to BWI Marshall Airport Amtrak, then shuttle to Ocean City, MD. 5 h 43 min $114. From Washington drive to Ocean City. 2 h 57 min $16.