The SJ&E was originally built to get men and supplies to the Big Creek Hydroelectric Project sites for the Pacific Light and Power Company (now Southern California Edison). The track was constructed for $1,055,728 by Stone & Webster Construction Company of Boston, the project's primary contractor. Grading commenced on February 16, 1912 and construction was completed on December 15, 1912. The 55 mile line started at El Prado (near Friant where it interchanged with the Southern Pacific Railroad. The SP branch continued on to Fresno where it intercepted the SP Mainline. From El Prado the line went east to Auberry and then terminated at Big Creek (Cascade/Cascada).