My son just got a new to us MTH Southern Pacific 4-8-4 with ProtoSound with Digital Reverse. The sound card doesn't work and the loco only goes forward. I can't make it go in reverse, even following the directions in the manual so we're looking to do another conversion to TMCC. I'm assuming either the AC Commander or Cruise Commander is the way to go. If I want to add sound, do I have to spend another $95 to get sound?