A transit plan is not effective and steps may not be taken to implement it until the plan has been adopted by the Secretary. The Secretary may not approve or adopt the location of corridors, routes, stations, and terminals in any political subdivision unless the locations have been approved by the legislative body of the political subdivision. If the legislative body does not advise the Secretary in writing of its action within 180 days after its receipt of notice of the proposed locations, the legislative body is deemed to have approved the location. Before the adoption, revision, or amendment of any transit plan, the Secretary shall send the proposed plan, revision, or amendment to the following, for comment to be made within the time that the Secretary specifies: The Governor; The chief executive officers and the councils or the boards of county commissioners in the District; The Public Service Commission; The Baltimore Regional Council of Governments; The Department of Planning; Each private carrier operating in the District; Each labor union representing employees engaged in transit operations in the District; The legislative representatives of any affected political subdivisions; and Any other agency that the Secretary determines.