As others have already stated, NCE does not support DC. That's a decision that they made from the get-go. The only systems that I know that will operate both DCC and one (1) DC address is Bachmann and Digitrax.
If a HO-scale decoder won't fit in the tender of your 0-6-0 switcher, a N- or Z-scale decoder probably will. I put a Z-scale Digitrax decoder in my Proto 2000 S1 switcher (w/o modifying the chassis) and I bet that has even less room than your 0-6-0.
Tom
