This route was built in 1887 as part of Southern Pacific's original mainline from San Francisco to Los Angeles. In the early 1900s it was bypassed by a parallel route further south, and this line became a secondary route. It ran parallel to the Santa Clara River for its entire distance, serving local orange groves and farms. It remained in service by SP until 1987, when the Santa Paula to Saugus segment was abandoned.
A local tourist railroad, Fillmore & Western, purchased the segment from Santa Paula east to Fillmore. The F&W operates passenger trains with historic equipment all year long. The F&W also has a large collection of rail equipment in Fillmore in various stages of repair. The Fillmore & Western also includes the Fillmore to Piru segment on its brochure maps, but there are no trains currently running on that part. The rails are intact, though solidly rusted, and the crossing signals have been upgraded where it crosses CA Route 126. East of Piru, the rails are completely removed. Much of the grade between Piru and Newhall Ranch is easily found as it runs parallel to CA Route 126, but the route is not a public trail. East of Newhall Ranch the route can be followed by local industries, under I-5 and an adjacent road (called the Old Road), to a bridge over the Santa Clara River. This bridge (see below) is used for water pipes but is blocked from public use. The right-of-way for the last mile to Saugus has been obliterated by the widening of parallel Magic Mountain Blvd. The line ended with a wye to the SP mainline between Los Angeles and Mojave, but most traces of the wye have been removed.
