(a) The Attorney General may, and on request of the Board shall, bring court proceedings to enforce this part, or a regulation or order of the Board or certificate issued under this part, and to prosecute a person violating this part or a regulation or order of the Board or certificate issued under this part. (b) The United States Government may bring a civil action on behalf of a person to compel a rail carrier providing transportation subject to the jurisdiction of the Board under this part to provide that transportation to that person in compliance with this part at the same rate charged, or on conditions as favorable as those given by the rail carrier, for like traffic under similar conditions to another person.