I'm thinking of getting some sound value Alco loco's, such as their RS 3.  I operate with standard DC and am wondering about their sounds.  Mainly automatic sounds.  I know I won't be able to blow the horn or ring the bell.  Will the horn blow automatically when I change direction?  Will the bell ring at slow speeds?  All I want is the sound of the Alco prime mover, and of course random air pumps etc.