Pasadena Subdivision
The Pasadena Subdivision is the remnant branch line of the former Atchison, Topeka & Santa Fe Railway Los Angeles Second District. The line currently branches off of the Metrolink San Bernardino line at Cambridge in Claremont. The line follows a generally east–west alignment, passing through the cities of Claremont, Pomona, La Verne, San Dimas, Glendora, and Azusa before coming to a truncated end in Irwindale.
The line was originally built by the Los Angeles & San Gabriel Valley Railroad in 1885. LA&SGV was sold and consolidated on May 20, 1887 into the California Central Railway. In 1889 this was consolidated into Southern California Railway Company. On January 17, 1906, the Southern California Railway was sold to AT&SF.
The line hosted the Desert Wind until 1986, and continued to serve the San Gabriel Valley and host the Southwest Chief until 1994, when the 1994 Northridge earthquake weakened the bridge over the eastbound lanes of Interstate 210 in Arcadia. In the late 1990s construction of the Gold Line started and opened on July 26, 2003.
In 2013 reconstruction along the former roadbed from Sierra Madre Villa to Azusa began with the Gold Line Foothill Extension, and was completed in late 2015. The line currently continues to APU/Citrus College Station, one mile past the site of the former Azusa Station; service started on March 5, 2016.