Light Bell Horn Air Release Coupling 1 Brake release/Squeal Dynamic Brake/Squeal Air Hose/Uncoupling Lever Shut Down/Notch Down Fan/Notch Up Rail Clack Traction Air Compressor Prime Mover Type Master Volume Decrease Master Volume Increase Air Compressor Flange Squeal Air Release Bell Type Horn Type Associated Loco Sound Bell Volume Horn Volume Diesel Rumble Volume Safety Valve Pop Air Release Flange Noise Sand Drop Air Release Horn 0 Horn 1 Horn 2 Horn 3 Horn 4 Horn 5 Horn 6 Horn 7 Horn 8 Horn 9 Horn 10 Horn 11 Horn 12 Horn 13 Horn 14 Horn 15 Horn 16 Horn 17 Horn 18 Horn 19 Horn 20 Horn 21 Off Range 0-22 Bell 0 Bell 1 Bell 2 Bell 3 Bell 4 Bell 5 Bell 6 Bell 7 Off Range 0-6 Auto notch - RPM and notch synchro to speed Manual notch - notch down/up with F8/F9