49 C.F.R. § 1150.22
The acquisition by a State of a fully abandoned line is not subject to the jurisdiction of the Surface Transportation Board. The acquisition by a State of a line approved for abandonment and not yet fully abandoned is exempted from the Board's jurisdiction. If the State intends to operate the line itself, it will be considered a common carrier. However, when a State acquires a rail line described under § 1150.21 and contracts with an operator to provide service over the line, only the operator incurs a common carrier obligation. The operators of these lines are exempted from 49 U.S.C. 10901 and 10903 which are the statutory requirements governing the start up and termination of operations. Operators exempted from these requirements must comply with the requirements of this part and must apply for a modified certificate of public convenience and necessity. The operator is a common carrier and incurs all benefits and responsibilities under 49 U.S.C. subtitle IV; however, the State through its operational agreement or the operator of the line may determine certain preconditions, such as payment of a subsidy, which must be met by shippers to obtain service over the line. The operator must notify the shippers on the line of any preconditions. The modified certificate will authorize service to shippers who meet these preconditions and the operator will be required to provide complete common carrier service under this certificate only to those shippers. (See 363 ICC 132.)
49 C.F.R. §1150.22