Tenn. Code Ann. § 65-6-103

It is lawful for any railroad company created by and existing under the laws of this state, and for any lessees of a railroad of such company, from time to time, to subscribe for or purchase the stock and bonds, or either, of any other railroad company or companies chartered by or of which the road or roads are authorized to extend into this state, when their roads shall be directly, or by means of intervening railroads, connected with each other; and to make contract with such company or companies for the construction, maintenance, repairs, or equipments, as well as lease of such other railroad or railroads, upon such terms as may be agreed upon by the companies owning the same, or by the companies and such lessees.