(a) Whenever the department, a county, or a municipality shall decide to eliminate any grade crossing on its respective public road system by means of an underpass or overpass, prompt notice of such decision shall be given to the railroad or railroads involved; and within 30 days thereafter the representatives of the department, the county, or the municipality and of the railroads involved shall meet and, within 90 days, agree to a plan and specifications for the construction of a grade separation structure. Any such agreement between a county or municipality and a railroad shall be submitted to the department for its approval; and work leading to the elimination of the grade crossing pursuant to the agreement shall not commence until and unless the department approves the same. The department, county, or municipality, by agreement with the railroad or railroads involved, may apportion the work to be done in the construction of such grade separation structure between the railroad or railroads and the department or the county or the municipality.

(b) If agreement is not reached within 90 days, the department, county, or municipality may proceed with construction of a grade separation structure or may by written order direct the railroad or railroads involved to proceed with the construction of a grade separation structure according to the plan and specifications accompanying such order, provided that no work shall be begun on any grade separation structure on a county or municipal public road system until and unless the department approves the plan and specifications of such structure. It shall be the duty of said railroad to begin work on any such grade separation structure within four months after receipt of an order to that effect and to complete that structure within a reasonable time, provided that the railroad shall not be required to do the actual physical work of providing approaches by fill to an overpass or the excavating beneath an underpass or the approaches thereto, although the cost of such work shall be considered as part of the costs of the grade crossing elimination, whether actually performed by the railroad, the department, the county, or the municipality; and such costs shall be apportioned as provided in Code Section 32-6-195. If the railroad does not begin work within four months after receipt of an order to that effect, the department, county, or municipality may proceed with the construction of the proposed grade separation structure. If the railroad begins work within four months after receipt of an order to that effect but thereafter fails to complete such work within a reasonable time, the department, county, or municipality may proceed to complete the unfinished work.

(c) In any case where the construction of all or part of a grade separation structure is done by the department, a county, or a municipality, a statement of any railroad's share of the costs of the project, as determined pursuant to Code Section 32-6-195, plus 8 percent per annum interest on each expenditure of the cost of such project shall be submitted to the railroad upon completion of the project. In the event that the railroad does not make payment or arrange to make payment to the department, county, or municipality within 60 days of receipt of the statement, the department shall certify the amount for collection to the Attorney General; or, in the case of a project on a county or municipal public road system, the county or municipality shall take appropriate action for the collection of the amount thereof. In the event said share is not paid within the time specified in this Code section, said share or any unpaid portion thereof shall bear interest at a rate of 8 percent per annum from the date due.

(d) The department, a county, or a municipality shall not construct or require any railroad to construct an underpass of a plan, specification, or design, the strength of which, in the judgment of the railroad, shall not be sufficient to meet the requirements of its traffic thereover. In a plan providing for an overpass or underpass, the department, a county, or a municipality shall not interfere with or change the grade or alignment of the track or tracks of any railroad or relocate the line of the railroad without its consent.