NEW! FACTORY INSTALLED QUANTUM SOUND SYSTEM WITH DUAL SPEAKERS! Sound features in the A unit include: Dual Diesel Engine Sounds, Horn, Bell, Squealing Brakes, Doppler Effect, Air Let Off (in neutral), Headlight, Slave (mutes whistle and bell for double heading) Sound can be operated with a standard DC power pack as well as DCC controllers. Powerful and Smooth Running Performance Close Coupling with Working Diaphragms