Horns for trains? GotLag's mod has horns, but they sound funny to me, and there's no controlling it. Louder train horns can draw the enemies from farther away, too.

I'll see if I can add this, at the same time as I update the mod, because I see that the creator is inactive

I wrote some code so that trains (including the ones from YuokiTani), helicopters and hovercrafts have honks too.
The trains from YuokiTani have two Diesel, two Santa Fe and one Steam version. In short and long length.
I also exchanged the tank honk.