I know it can be done (sort of), but this has to do with an existing older layout that has three power blocks, but no programming track. This isn't mine, I'm tiring to help out a fellow MRR that isn't familiar with DCC. The layout is kinda large, it's HO scale in his basement. He has Digitrax system and his locos are 20 or so years old (Proto 2000, Broadway Limited & Life Like) , originally equipped with DCC decoders, if any of that matters. Most of his power AFAIK were never programmed or are programed wrong. If all the locos are removed from one power block segment (assuming both rails are gapped), would that be ok to program a DCC equipped loco? Lastly, I have little experience with DCC, the above is assuming that will change shortly.