I actually found out what's going on . I know somebody that works for Huntsman Chemical and called and asked them why all the horn blast . While the rock load or string of tank cars are going threw the switching part of the tracks that lead into the yards . The engineer makes those short blast to let workers be alert that the train load is moving into one of the yards in route to the loading and unloading platforms . Also I've noticed the engineer makes the normal horn blast when crossing public crossings such as street and road crossings .