"Street railroad" includes every railway, and each branch or extension thereof, by whatsoever power operated, being mainly upon, along, above or below any street, avenue, road, highway, bridge, or public place within any city or city and county, together with all real estate, fixtures, and personal property of every kind used in connection therewith, owned, controlled, operated, or managed for public use in the transportation of persons or property, but does not include a railway constituting or used as a part of a commercial or interurban railway.
Ca. Pub. Util. Code § 231