(1) Not later than May 15 in each year, the state board of assessors shall prepare an assessment roll upon which they shall set forth the true cash value and taxable value on the immediately preceding December 31 of all the property of the companies subject to taxation under this act. A determination of true cash value and taxable value is not final until reviewed as provided in this act. For the purpose of arriving at the true cash value and taxable value of the property on the assessment roll, the state board of assessors may personally inspect the property assessed, may consider the reports filed under this act or reports and returns filed in the office of any officer of this state or in the office of any other governmental agency, and any other evidence or information obtained or possessed by the state board of assessors.

    (2) In determining the true cash value and taxable value of the property of a railroad, union station, and depot company that owns, leases, operates, or uses lines partly within or partly outside of this state, the state board of assessors shall consider the proportion of the number of miles of all track controlled or used by that company within this state to the entire mileage of all track controlled or used by that company both within and outside of this state. The state board of assessors shall also consider any other uniform factors that reflect a fair allocation of value to this state.

    (3) For tax years that begin before January 1, 2006, in determining the true cash value and taxable value of the property of a telegraph company or telephone company that owns, leases, operates, or uses lines partly within and partly outside of this state, the state board of assessors shall only consider the proportion of the number of miles of telegraph or telephone lines controlled or used by that company within this state to the entire mileage of telegraph or telephone lines controlled or used by that company both within and outside of this state. The state board of assessors shall also consider any other uniform factors that reflect a fair allocation of value to this state.

    (4) In determining the true cash value and taxable value of the property of an express company, the state board of assessors shall determine the actual value of the entire amount of the capital stock and bonded indebtedness of that express company. From that amount, the state board of assessors shall determine and deduct the actual value of all real property owned by that express company, and the actual value of all personal property owned by that express company that is not used in the express business of that express company. The state board of assessors shall then divide the remaining amount by the total number of miles, as determined by the state board of assessors, of railroad, stage, water, and other routes over which the company did business to obtain the value per mile. The state board of assessors shall then multiply the value per mile by the total number of miles of the routes within this state, as determined by the state board of assessors. The state board of assessors shall then add to the product of that calculation the value of all real estate owned by that express company in this state, as determined by the state board of assessors. The sum of this calculation is the actual value of the property of that express company subject to assessment and taxation in this state.

    (5) If the state board of assessors determines that the ocean routes of a company are so different in character from its other routes that the mileage basis of apportionment of the value of the entire property to be apportioned in this state would be unfair if the full mileage of the ocean routes were included, the state board of assessors may make an allowance for that company’s ocean routes to bring those ocean routes to parity with that company’s other routes. In making this determination, the state board of assessors shall consider the relative mileage values and earning capacities of the ocean routes and the other routes and shall require special reports of the character, mileage, earnings, and value of the ocean routes. The state board of assessors may exclude from its determination of aggregate mileage any ocean routes on which the express company fails to furnish the requisite reports, but no further penalty shall be imposed for the failure to report the mileage of ocean routes.

    (6) If a company claims in writing that the mileage basis of apportionment of the value of the entire property to be attributed to this state is unfair, the state board of assessors shall make the apportionment that in its judgment is fair. In making that apportionment, the state board of assessors shall consider the mileage within and outside of this state, making any necessary allowance for ocean mileage as provided in this section.

    (7) In determining the true cash value and taxable value of the property in this state of car loaning, stock car, refrigerator, fast freight lines, and other car companies, and other companies owning, leasing, running, or operating cars subject to taxation under this act, the state board of assessors shall consider the proportion of the aggregate car mileage made or run by the entire number of cars owned or operated by a company to the car mileage made or run by the entire number of cars owned or operated by that company within this state.