Whenever at any alarm or fire, any fire engine, hose cart or other fire apparatus approaches any drawbridge for the purpose of crossing the same, toward such fire, the captain, bridge tender or other person in charge of the draw, shall, if such bridge is open, lower the signal and close the draw as soon as practicable, or if closed, keep closed until such engine or other fire apparatus has had an opportunity to pass over the drawbridge, notwithstanding vessels or boats may thereby be delayed.