When a person or corporation operates a line of railroad located partly within and partly without this State, except as otherwise provided, the Director shall appraise at its fair and just value all property within this State acquired, constructed, or used in this State for railroad business or purposes held, possessed, or owned by the person or corporation operating such line of railroad. In making such appraisal, the Director may take into consideration the value of the entire railroad system operated by such person or corporation, the mileage thereof both within and outside this State, its engines, cars, and other equipment and other information, facts, and circumstances as will aid him or her therein. (Amended 1977, No. 105, § 14(a).)