Good morning all I have two Athearn GP15s that I am very happy with except for the horns. I would like to replace them with regular detail parts but I'm a bit confused. I realize that RR constantly changed and moved appliances but I've seen pictures with a 5 chime horn with all bells facing forward and others with 3 forward two facing back, what horns did the Frisco use on there GP15s please? I also want to download the correct sound for the proper horn. Thank you much!