Tenn. Code Ann. § 65-3-203

In case of default in the payment of any such fee, or part thereof, when the same shall become due, as provided in this part, any railroad in default shall be liable to a penalty of ten percent (10%) per month on the amount of the fee, which may be recovered by suit of the state for every month it remains in default, and any such penalty, when collected, is to be deposited in the state treasury as part of the railroad account.