Cal. Veh. Code § 35789
Any housemoving contractor or other person who by contract or otherwise moves or transports a dwelling house or other building across railroad tracks shall furnish to the division or district superintendent of the railroad company operating such tracks written notice of intention to make such movement at least 36 hours prior to doing so. The written notice of intention to make such a movement shall contain the name of the street, highway or road over which such dwelling house or other building will be moved across the railroad tracks, the approximate time of day such movement will be made and such other information as may be necessary to enable the railroad company to take precautionary measures to avoid a collision by a train with such dwelling house or other building.
Ca. Veh. Code § 35789