Some of the most enduring images of old New York are turn–of–the–century streetscapes with the graceful steel skeletons of the “El” tracks rising above. These images date from a project that started in 1867, when the city built elevated train tracks on thirty–foot steel trestles as the first real urban rapid transit system anywhere in the United States. The trains were noisy and dirty, dropping soot and dust on the streets below, but the system was a triumph of civil engineering and carried millions of passengers throughout the city until the 1920s. A few elevated train tracks from the 1890s can still be found in Brooklyn. Most of them, however, were abandoned and torn down in favor of subways.