The Oakland Subdivision was the westernmost route of the Western Pacific and the original route of the California Zephyr. The portion of the Oakland Subdivision between Union City and Oakland was relegated to industrial spur status after Union Pacific merged with Southern Pacific in 1996, as UP chose to operate on SP's parallel route, the Mulford Line, instead of the Oakland Sub.
Most of the line is completely abandoned; however, there may or may not be a few industrial customers left on isolated portions on the line. Some sections of the line are used as access roads, and the Oakland Intermodal Gateway has been built over the former yard at Oakland.
See also Oakland, California.
Thanks to Paul Carr for contributing information about this route.