The Ninth and Sixth Avenue Elevated trains, constructed in the second half of the 19th century, were built as an answer to the city's growing congestion problem. By the 1940s the Els were outdated and inefficient in comparison to the newly constructed modern subways. Between 1939 and 1958 (largely though in 1939 and 1940) the massive steel structures were dismantled piece by piece.

This series is the complete line of the Ninth Avenue El as it existed between the 1870s and 1940.

"The New York Elevated Railroad Company built a line on Third Avenue to 129th Street at the Harlem River in 1878; a year later the company upgraded the Ninth Avenue line and extended it to 155th Street in northern Manhattan. The Gilbert (after 1878, Metropolitan) Elevated Company built and opened a line on Sixth Avenue to 58th Street in 1878, built a connection to the Ninth Avenue line on 53rd Street, and by 1880 completed a line on Second Avenue. In 1879 the companies merged to form the Manhattan Railway Company. By 1880 all four elevated lines had reached the Harlem River. Early in 1954 the New York City Transit Authority, NYCTA, which succeeded the Board of Transportation, concluded that the Third Avenue line was no longer needed south of 149th Street. Supposedly, the Lexington Avenue subway and East Side buses had adequate capacity to carry former Third Avenue riders in Manhattan. In the best interests of the city, the El would be closed and demolished. With one exception, the Third Avenue El fleet was destroyed..." For more on the Third Avenue El, check out this article by Lawrence Stelter in Gotham: A Blog for Scholars of New York City History.