Miss. Code Ann. § 27-35-301

The members of the State Tax Commission are constituted state assessors of railroads and other public service corporations, and they shall, upon the receipt or making of the schedules hereinafter provided for, assess the property of railroads, telegraph, telephone, sleeping car, express, electric power and light companies and other public service corporations liable to taxation in the state, affixing its true value so that such property shall bear its just proportion of taxation, taking into consideration the value of the franchise and the capital engaged in the business in this state. The state assessors of railroads and other public service corporations may adopt other and further rules necessary and proper to ascertain the value of property to be assessed by them, including the value of the franchise and amount of capital engaged in the business in this state. Provided, however, the members of the State Tax Commission shall be assessors of railroad and Class IV public service property, but shall not be the assessors of the types and kinds of properties owned by the public service corporations and appraised and assessed by county tax assessors pursuant to Sections 27-35-331 through 27-35-341.