In 1912 the Northwestern Elevated Railroad (today's Chicago Transit Authority Purple Line) extended its service into Wilmette. This occurred without permission from the village, as the tracks were extended from the route's existing terminal in Evanston into the village's border under the cover of darkness before the morning of April 1, 1912. Later that year, a second track was added in Wilmette and the station's platform was elongated. In 1913 the tracks were extended deeper into the village and the makeshift station that had been constructed under the cover of darkness was replaced with two new stations in Wilmette at Isabella and Linden, the latter of which was designed by Arthur U. Gerber and served as the line's terminus.