The Sacramento Northern Railroad, a subsidiary of Western Pacific, came into existence around 1929, and was composed of the Oakland, Antioch & Eastern Railroad (also the San Francisco-Sacramento Railroad, originally the Oakland and Antioch Railway), and the Northern Electric Interurban; each of these former lines were in service as early as 1900. Originally electrified, the line converted to diesel in the 1960s. The SN disappeared when Western Pacific was merged into Union Pacific in 1982.
When the Bay Bridge opened between San Francisco and Oakland, Sacramento Northern trains used the tracks on the lower deck. The tracks on the bridge have been gone for decades, but the subject of rebuilding a transit line there is raised from time to time. Meanwhile, most of the mainline and branches have been abandoned, some segments are still in use or were rebuilt for new uses:
1. Yolo Shortline runs the line from Woodland through West Sacramento south to Tasco.
2. Sacramento's Light Rail line was rebuilt over the right-of-way of the Swanston branch northeast of downtown Sacramento.
3. The Western Railway Museum has acquired 20 miles of the former right-of-way between Sacramento and the Bay Area. The volunteers of the WRM rebuilt the track, and re-strung and energized overhead trolley wire along the way, allowing them to run excursions using vintage streetcars and interurbans (see picture below).
4. Bay Area Rapid Transit (BART) rebuilt a section through the hills east of Oakland, between Walnut Creek and North Concord.
Rockville Branch: The Sacramento Northern's Rockville Branch served agricultural areas of Solano County. The branch was Y-shaped, and connected to the SN main over tracks that are now operated by the Western Railway Museum. The branch crossed over the Southern Pacific Oakland-to-Sacramento mainline on a bridge, and then divided into two legs. One branch headed north-northwest to Vacaville, while the other headed southwest to Fairfield (near Rockville). These routes were abandoned after packing houses switched to trucks or closed, and the associated farmland was sold to developers.
Montezuma, CA: Just north of the Sacramento Northern's ferry crossing of the Sacramento River at Suisan Bay, the line ran through low-lying marsh land and across sloughs near Montezuma. There are many remains of the former SN in this area.
Thanks to Richard Vantine and Jack Witthaus for contributing information about this route.