Miss. Code § 19-29-13
In any suit, action or proceeding involving the validity or enforcement of, or relating to, any contract of a county railroad authority, created pursuant to Section 19-29-7, the county authority shall be conclusively deemed to have become established and authorized to transact its business and exercise its powers upon proof of the adoption by the county of the resolution creating the county railroad authority and of the appointment and qualification of the first commissioners thereof.
In any suit, action or proceeding involving the validity or enforcement of, or relating to, any contract of a regional railroad authority, such regional railroad authority shall be conclusively deemed to have become established and authorized to transact its business and exercise its powers upon proof of the issuance by the Secretary of State of a certificate of incorporation of such regional railroad authority.
Miss. Code § 19-29-13