California Code, Revenue and Taxation Code - RTC § 11271

(a) Every person whose private railroad cars are operated upon the railroads in this state at any time during a calendar year shall file with the board on or before April 30 a report under oath setting forth specifically the information prescribed by the board to enable it to make the assessment required in this part.

(b) In the case of a corporate owner of property, the property statement shall be signed either by an officer of the corporation or by an employee or agent who has been designated in writing by the board of directors to sign such report on behalf of the corporation.