The Attorney General shall represent the Government in the actions specified in and in enforcement actions and actions to collect civil penalties under subtitle IV of title 49.section 2321 of this title
The Surface Transportation Board and any party or parties in interest to the proceeding before the Board, in which an order or requirement is made, may appear as parties of their own motion and as of right, and be represented by their counsel, in any action involving the validity of such order or requirement or any part thereof, and the interest of such party.
Communities, associations, corporations, firms, and individuals interested in the controversy or question before the Board, or in any action commenced under the aforesaid sections may intervene in said action at any time after commencement thereof.
The Attorney General shall not dispose of or discontinue said action or proceeding over the objection of such party or intervenor, who may prosecute, defend, or continue said action or proceeding unaffected by the action or nonaction of the Attorney General therein.