The state board of equalization, at its annual meeting in July in each year, shall assess, at its actual value on the first day of January of that year, the operating property, including franchises, of each railroad operated in this state, including any electric or other street or interurban railway. If any railroad allows any portion of its railway to be used for any purpose other than the operation of a railroad, the portion of its railway while so used must be assessed in a manner provided for the assessment of other real property. To enable the board to make a correct valuation of property, it shall have access to all reports, estimates, and surveys of a line of railroad on file in the office of the public service commission and has power to summon and compel the attendance of witnesses, and to examine witnesses under oath in any matter relating to the value of the property. In fixing the value of any railroad, and of branch lines and sidetracks, the board must be governed by the rules prescribed for county and township assessors in valuing other property in this state. The board shall make a record of the value placed by it upon the property of the railroad, including the valuation per mile [1.61 kilometers] of main line and of branch lines and sidetracks. Railroad property held in trust by the public service commission for purposes of reorganization or reopening of the railway line is exempt from assessment as provided in this section.