Section 84. If the county commissioners of a county, the board of aldermen of a city or the selectmen of a town where a bridge at the crossing of a public way and a railroad, or a bridge upon which a railway company is authorized to lay and use tracks, is located in whole or in part, or the directors of a corporation owning or operating such railroad, or the directors of a company owning or operating such railway, are of the opinion that such bridge is in need of maintenance or repair, they may apply to the department, which shall, after public notice, hear all persons interested, and, if it decides that the work of maintenance or repair is necessary, shall prescribe the manner in and the limits within which it shall be done, and shall forthwith certify its decision to the parties.