This abandoned Western Pacific line was originally constructed as the Alameda & San Joaquin Railroad. It headed south from Stockton and then turned west into Corral Hollow to Tesla, probably to serve mines and mineral extraction. When WP acquired this route, probably in the late 1800s, the segment between Stockton and Carbona became part of WP's main line (still in service today). The portion from Carbona to Tesla became a branch.
The branch segment has been largely abandoned, much of it many decades ago. About a half-mile in track remains in service, although it appears to be little used. The active segment ends at a gravel pit next to Mac Arthur Road.
The middle portion of the abandoned segment can be seen from Corral Hollow Road where it passes through open range land. This area is undeveloped, and the right of way can be seen as it passes along a ledge on the south side of the hollow. The western end of the branch could not be traced; it has had some development, and some of the hollow is used for dirt bike competitions.
Thanks to Mike Palmer for contributing information about this route.