(en) Mark S. Feinman, « Continuing the Story of the 9th Avenue El » (consulté le ) : « On April 1, 1903, the entire Manhattan Elevated system was leased to the IRT Company for 999 years. Subway system construction was planned to connect with the Els at various points. By June 25th, 1903, the last steam-powered elevated train was operated in passenger service on the 9th Ave El. »