No sound from cars

I have a bunch of JR stuff in my T:ANE route and it seems that when I open the route up in Driver Mode, the JR cars that I have already placed there (in Surveyor) won't play their bogey sounds or sounds from the lilb library (brakes, etc.) when I move them around my route. When I drop in new cars in Driver Mode, however, the sounds play. Is there a way to fix this? I hate having to go back and add loads to new cars I just dropped in in Driver Mode every single time I open a session...