Legal Question in Real Estate Law in California

It's called a lawsuit to quiet title.

Based on your Zip code, I'd say the property in question is part of the right-of-way of what was once the Southern Pacific's Rumsey Branch, also called the Capay Valley line and, later when its northern terminus was cut back, the Winters Branch. Finally, in about 1970, the line was cut back from Winters to Vaca Valley. I helped prepare the ICC abandonment application for the SP.

Railroad right-of-way is/was held in various ways, including outright fee simple, ordinary easements, and ownership subject to reversion upon abandonment. I do not remember the status of the right-of-way land on this line, if I ever knew.

"Abandonment" of a railroad has two meanings, or perhaps better, takes place in two phases: regulatory permission to discontinue common-carrier service, cancel tariffs, etc., and physical removal of the rails, etc. Abandonment, including cessation of service and removal of the track does not, however, equate to abandonment of ownership of the real estate. If the land is reversionary, the land reverts back to the successors of the grantees at the time the railroad was built. If the railroad owns the land in fee, it continues to own it. Further, in California, it is not subject to adverse possession so long as the railroad continues to pay the property taxes, which I can assure you it does.

Real property itself cannot be abandoned. Certain interests in land are subject to abandonment, such as easements, or defeasance, such as land subject to a reversion upon failure of a condition in the deed.

So, your first step is to determine the character of right, title or interest the railroad acquired at the time of construction. This and related information about the successors to the original owners will be very helpful in deciding whether to sue for quiet title and whom to sue, or whether the SP's successor, Uniion Pacific, should be contacted with a request to quitclaim to you, probably for a far lesser sum than the cost of a quiet-title suit.