We are planning a modded multiplayer run and the thing is that train horn settings are saved per game/map so there is no way to disable it just for oneself wich means that we have some players that are annoyed of the sounds especially in the lategame. This is where i suggest making the train horn settings player based so that everyone can play with the sounds they like instead of a global setting.

That's a pretty complicated change to make, I don't have time to work on it, and it might hurt performance as well. I suggest you try adjusting the settings so the sounds travel less distance and fewer sounds are created. Or maybe this mod is not good for your server.