Simple: Change the horns on each locomotive. Typically a Gp38-2 and a ES44DC have different horns. And allow us to change the amount of air we use, making a softer / quieter horn, or a louder fully pulled down handle. The horns currently with CSX don't sound realistic and for the most part most US ones don't sound too great. But 3rd party modders do a better job that Dovetail with sound designs so I might just wait for that.
Some of the routes have pretty good and accurate horns such as peninsula corridor, northeast corridor, and Long Island Railroad. But I do agree some routes really need change to their horns such as CSX Sand Parch Grade and Oakville Subdivision. Sand patch grade just slapped the same horn on all train to bring no variety. Oakville decided to use the most generic train horn in all of train simulator history. Dating back all the way to the old trainz simulators. It’s a very bad and inaccurate horn and desperately needs change.
There are some horrifically looped horns on here. The original Trainz had better than some of these, which is quite embarrassing to say the least. Makes you dread those whistle boards instead of being able to blast the horn with pride (and maybe a little menace in the case of the American locos)