The Gaithersburg Wye, on 2.25 acres beside the Metropolitan Branch of the old Baltimore and Ohio Railroad, served as the terminating point for trains from Washington traveling west. Because steam locomotives arriving in Gaithersburg needed to be turned around to reverse direction, the railroad used a wye, a three-legged track arrangement attached to the main line in the shape of a Y. Its two legs formed back-to-back concave arches with curves slight enough to handle the wheelbase of the largest locomotives turned there. The wye dates to 1888, when Gaithersburg was undergoing growth and modernization inspired by the opening of the Metropolitan Branch of the B&O Railroad.