Those are wagon sounds and I've got them. I actually prefer the RWSO sounds anyway. I'm trying to get track rumble in the cab for a more realistic drivers' experience.
This might be adressed with Krellnut's new wagons sound pack (soon to be released). Also you might be able to make the sound audible in the cab by editing the audio blueprint for the engine. See document 8.01 Audio Control and Blueprints.pdf for details.