So basically on most American trains irl you can quill the horn. Basically you just dont pull the horn lever all the way down. Or press the button all the way. It doesn't send air into all the bells of the horn causing it to be not as loud. And in some cases sound completely different. Also with American trains that it doesn't matter if you push or pull the horn lever make it so it automatically pulls it just like irl. Probably a good keybind would be SHIFT+ SPACE, to quill the horn. When you release shift but still keep your hand on space it gives it full blast.
Kind of reminds me of my model trains. I have Lionel's Legacy Control System on my O-Gauge layout in my room. The system allows users to quill the horns/whistles on locomotives. It's pretty cool. This is a great feature for both Train Sim Classic and Train Sim World.
