Such boards need not be put up at the crossing of streets and alleys in cities, towns, or villages, but such inclined cable railroad company shall be subject to such proper regulations made by the municipal authorities, in pursuance of general municipal powers, regulating speed, passage, and flaggers in such municipalities; and at crossings, and where there are sidings and switches, the whistle shall always be blown at a distance of not less than two hundred fifty (250) yards from every crossing of a public road.