((a)) Any person, any body politic, or municipal organization, or State commission, complaining of anything done or omitted to be done by any common carrier subject to this chapter, in contravention of the provisions thereof, may apply to said Commission by petition which shall briefly state the facts, whereupon a statement of the complaint thus made shall be forwarded by the Commission to such common carrier, who shall be called upon to satisfy the complaint or to answer the same in writing within a reasonable time to be specified by the Commission. If such common carrier within the time specified shall make reparation for the injury alleged to have been caused, the common carrier shall be relieved of liability to the complainant only for the particular violation of law thus complained of. If such carrier or carriers shall not satisfy the complaint within the time specified or there shall appear to be any reasonable ground for investigating said complaint, it shall be the duty of the Commission to investigate the matters complained of in such manner and by such means as it shall deem proper. No complaint shall at any time be dismissed because of the absence of direct damage to the complaint.
((b))
((1)) Except as provided in paragraph (2), the Commission shall, with respect to any investigation under this section of the lawfulness of a charge, classification, regulation, or practice, issue an order concluding such investigation within 5 months after the date on which the complaint was filed.
((2)) The Commission shall, with respect to any such investigation initiated prior to , issue an order concluding the investigation not later than 12 months after .
((3)) Any order concluding an investigation under paragraph (1) or (2) shall be a final order and may be appealed under .