California Code, Revenue and Taxation Code - RTC § 11203

(1) Freight train or passenger train cars owned by railroad companies which are used or subject to use under the ordinary per diem agreement common to all railroads.

(2) Freight train or passenger cars handled under mileage or through line contract arrangements between railroad companies.

(3) Cars owned by or leased to any railroad company operating in this state, or by any railroad company operated as a part of the same railroad system as the company operating in this state, and used by the railroad company in the operation, maintenance, construction, or reconstruction of its property and assessed and taxed in this state as a part of the property of a railroad company operating in this state.

(4) Passenger train cars that are privately owned and for which the owner pays the railroad a fee, regardless of how calculated, for transporting the cars.

(5) Any railroad rolling stock for which a railroad or the National Railroad Passenger Corporation is the lessee. For a leased car, the car's Association of American Railroad's, or successor organization's reporting mark is rebuttably presumed to be the mark of the lessee.