One thing I've noticed that's been bugging me is the train sounds are louder in my right ear while controlling an engine, as if the character actually sits beside the train. Hopefully this is something that can be fixed easily, or just an issue with my setup.

this is due to the sound position, the sound comes from the current position of the front right corner of the entity hitbox.

Generally it's standard sound logic for the game. There are plans to fully replace this system due to it's bugs and limitations in later versions of TC5.

for TCCE that could potentially be fixed by playing the sound from the rider entity, although that will mean having different sound logic depending on if the player is on the train or not. And considering TCCE builds are mainly community maintained now, it's hard to say what will happen there.

thank you for everything you do, blue. we all love you for looking after this mod and putting in your heart and soul. keep on railroading