Atlas Master? Series Gold Additional Features: (Item #s 7038-7095) -Electronic Dual-Mode? Decoder (e-DMD) that allows your locomotive to run in DCC or traditional DC QSI? Quantum System? Features Including: (Atlas Master Series Gold locomotives only) -Dual speaker system -Authentic diesel engine sounds -Squealing brakes -Doppler effect -Air let-off in neutral -Coupler impact sounds when operated with DCC -Helper mode that mutes the whistle and bell for double heading -And more!