The line shares tracks with the Green Line from L'Enfant Plaza northward to Greenbelt. It is a quick link between downtown Washington and National Airport, and shares nearly all of its track with either the Green or Blue Line. The Yellow Line has only two stations that are not shared by any other lines (Eisenhower Avenue and Huntington), and only two sections of track that are not shared by any other lines – the section at the south end of the line, and the section between the Pentagon and L'Enfant Plaza stations, crossing the Potomac River.