California Code, Penal Code - PEN § 587a

Every person, who, without being thereunto duly authorized by the owner, lessee, or person or corporation engaged in the operation of any railroad, shall manipulate or in anywise tamper or interfere with any air brake or other device, appliance or apparatus in or upon any car or locomotive upon such railroad, and used or provided for use in the operation of such car or locomotive, or of any train upon such railroad, or with any switch, signal or other appliance or apparatus used or provided for use in the operation of such railroad, shall be deemed guilty of a misdemeanor.