In 1919, Spreckels completed the San Diego and Arizona Railway, a short line American railroad, dubbed "The Impossible Railroad" by many engineers of its day due to the immense logistical challenges involved. Established in 1906 to provide San Diego with a direct rail link to the east by connecting with the Southern Pacific Railroad (which secretly provided the funding for the endeavor) lines in El Centro, California, the 148-mile (238-kilometer) route of the SD&A originated in San Diego and terminated in the Imperial County town of Calexico.