California Code, Fish and Game Code - FGC § 2012

Every railroad corporation shall erect and maintain fences on both sides of its road, of the height and strength of a fence required by law, with openings, gates or bars therein at farm crossings or the roads for the use of proprietors of lands adjoining such railroad. Every such corporation shall also construct and maintain cattle guards at all the road crossings suitable and sufficient to prevent cattle and other animals from getting on the railroad. Until such fences and cattle guards have been duly made the corporation shall be liable for all damages which are done by their engines and cars to cattle, horses or other animals thereon.

After such fences and guards are duly made and maintained the corporation shall not be liable for any such damages, unless negligently or wilfully done. If any person rides, leads or drives any horse or other animal upon such railroad and within such fences and guards other than at farm crossings without the consent of the corporation, such person shall for every such offense forfeit not more than $10 and shall also pay all damages which are sustained thereby to the party aggrieved. No person other than those connected with or employed upon the railroad shall walk along the tracks of any such railroad, except when the same are laid along public roads or streets.