To be clear, when you asked about CV19,I understood you to mean after building the consist on NCE, in which case CV19 will have the consist address. If you meant after building the consist on Digitrax, without using advanced consisting(you can do advanced consisting on Digitrax, but will save that for later), then CV19 will have 0.
I'm fairly certain that none of the decoders on the market regulate the voltage to the motor if you're using the term regulate in the sense that the decoder applies the same voltage at the same speed step no matter what the input voltage. In Digitrax's discussion of speed steps they talk about the motor voltage being a percentage of the available voltage. However, even this doesn't accurately describe what is happening. Most decoders are using pulse width modulation in some form and because everybody doesn't use the same frequency or use the exact same control circuitry the decoders aren't necessarily going to respond to changes in track voltage identically. I'm not saying I know for a fact this is what's causing your problem, but it's fairly easy to check if you have meter that can measure DCC voltage. If the track voltage is different try setting the two layouts to match and see if the problem goes away.
I have a Digitrax system at home but use an NCE system at my club. When I speed matched engines with Digitrax decoders at home, they were poorly matched when running on the NCE system the club. The solution was to set CV 57 to 66 on all my Digitrax-equipped engines, a value recommended on another post. I have not have any problems since then.
That should be 102 decimal, which is 66 hexadecimal. That setting enables bemf and maintains the same setting for when in a consist and when not. If you want bemf, that is they way to go. Since spidge seemed satisfied with the way the Digitrax equipped engines ran when in an advanced consist(with bemf disabled), I decided to keep it simple and tell him to disable it across the board. By porgramming CV57 to 102 the engine should perform the same whether in an advanced consist or not, but he would have to re-speed match the engines since they seem to be speed matched with bemf off.
