Dave O,
Thanks for the additional info. Will the new railroad sound cars work with traditional analog/curved/sinusoidal wave form AC as well as with chopped? I was disappointed to discover (post-purchase) that AF steam and diesel sound box cars only work with chopped. Unfortunately just prior to buying them I had moved from TPC400's (chopped AC) back to 30B's (curved), so both of those sound cars are now instead just heavily weighted more expensive than usual box cars.
Dave