How do I change the momentum setting? : LUSENET : Wiring for DCC : One Thread

I have a digitrax decoder in my Kato genesis locomotive. It starts off so slow and takes so long to get up to speed and then usually goes too fast. I want to change this to be more in my control. I have an Atlas commander and a separate programing track. I had no trouble setting the address on this Locomotive, but I can't seem to understand how to work with the momentum. I've tried at 14,28,and 128 but it doesn't seem to change. What should I do and should I do it on the programing track or the main line... help... Don

-- Donald R. Santoro (, November 30, 2004



Please see my website for an explaination of DCC momentum control.

Put your speed steps back to 128 if you Atlas commander supports that. Speed steps have nothing to do with momentum.

Changing CV 3 & 4 (for momentum) is typically done on a programming track. Some systems support programming on the main line - a very handy feature if your system has that. Consult your manual on how to change CV's.

-- Allan Gartner (, November 30, 2004.

In addition to Allen's answer about cv's 3 and 4, I'd like to point you to cv's 2,5 and 6. These control the start voltage, max voltage, and middle voltage. CV 5, max, can lower the top speed of a locomotive. I have an On30 shay that ran way too fast at the top throttle setting, by changing cv 5 it now runs at about 15 SMPH at top speed. Thats way too slow for a diesel, but you can easily get it right by playing with the number you put into that CV. The digitrax decoder manual is here: The section on cv's 2-6 starts on page 36.

-- Steve Wilbur (, December 02, 2004.

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