Cal. Pub. Util. Code § 7530
Every railroad corporation in this State shall, within a reasonable time after its road is finally located, make a map and profile thereof, and of the land acquired for the use thereof, and the boundaries of the several counties through which the road may run, and file it in the Office of the Secretary of State. Every railroad corporation shall file like maps of the parts of the railroad located in different counties in the office of the clerk of the county in which such parts of the road are, there to remain of record forever. The maps and profiles shall be certified by the chief engineer, the acting president, and the secretary of the company. Copies of the map and profiles, so certified and filed, shall be kept in the office of the secretary of the corporation, subject to examination by all parties interested.
Ca. Pub. Util. Code § 7530