At every temporary crossing, established in accordance with section 7210, boards with the words "Temporary railroad crossing, stop, look, listen" distinctly painted on each side, in letters plainly legible, shall be placed on each side line of the railroad right-of-way at the crossing, on a post or other structure, in a position as to be easily seen by persons about to cross the railroad at those places. For any crossing so established, engine bells shall be rung and engine whistles sounded, as provided in section 7214.   [PL 1989, c. 398, §8 (NEW).]