Section 23. If the department is of opinion that repairs are necessary upon any railroad or railway, or that an addition to its rolling stock, or an addition to or change or relocation of its stations or station houses or waiting rooms, or a change in its rates of fares for transporting freight or passengers, or in the mode of operating the railroad or railway and conducting its business, is reasonable and expedient to promote the security, convenience and accommodation of the public, it shall in writing inform the corporation or company of the improvement and changes which it recommends.