§ 239. Joint liabilities of towns and their joint contracts. Whenever any two or more towns shall be liable to make or maintain any bridge or bridges, the same shall be built and maintained at the joint expense of such towns, without reference to town lines, except where the board of supervisors has otherwise apportioned such expense as provided in section two hundred and seventy-four. The town superintendents of all the towns, or of one or more of such towns, the others refusing to act, may, when directed by their respective town boards, enter into a joint contract for making and repairing such bridges.