After the service of an order under this subchapter, it shall be the duty of the bridge owner to prepare and submit to the Secretary of the department in which the Coast Guard is operating, within a reasonable time as prescribed by the Secretary, general plans and specifications to provide for the alteration of such bridge in accordance with such order, and for such additional alteration of such bridge as the bridge owner may desire to meet the necessities of railroad or highway traffic, or both. The Secretary may approve or reject such general plans and specifications, in whole or in part, and may require the submission of new or additional plans and specifications, but when the Secretary shall have approved general plans and specifications, they shall be final and binding upon all parties unless changes therein be afterward approved by the Secretary and the bridge owner.