It's easier and cheaper to put decoders in HO scale, and you can put speakers large enough to actually give decent sound in HO locos. But you can have a more complex layout in the same space with N.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Some people use both. HO in the foreground and N in the background to give a forced perspective illusion of greater depth.
Dave
Lackawanna Route of the Phoebe Snow
This is from the perspective of guy who models in small spaces (4x6 layouts in HO have been typical of my experience) in HO and HOn3. And I would recommend N scale based on the constraints you gave.
A 2x4 layout in HO, even if only a "diorama" doesn't provide enough space or track to justify DCC. Locomotives have to be very small to not overwhelm the layout even with simple movements. I'm not sure your existing roster is suitable for the realities of an HO 2x4. And regardless fo whether you contemplate a continuous loop or not, operating 2 trains with separate operators is an exercise in keeping out of each other's way - both physically and control-wise. Bottom line is that very few HO micro-layouts use DCC; the gains are generally not worth the extra expense and trouble of modifying locomotives and installing a DCC system.
N scale, on the other hand, allows you to put nearly the equivalent of an HO 4x8 in the same 2x4 space, should you choose. At this point, you have the space (barely) to run more typical locomotive rosters and rolling stock. And, depending on track layout, you can have 2 operator/train operation, and thus gain some benefits from your DCC investment.
Most modern N locomotives are set up around a drop-in decoder DCC install. Decoder manufacturers produce specific decoders for specific N locomotives, just like Micro-Trains produces specific coupler/pilot combinations for specific locomotives. The small HO locomotives that fit on a 2x4 layout, if not DCC-ready, will actually be more difficult to convert than most N locomotives.
my thoughts, your choices
Fred Wright
If you are talking about installing decoders in your existing engines, then HO will be easier. Decoders have gotten smaller, and there are plenty of them that fit nicely in N-scale engines. However, older engines were often designed with very little empty space under the shell, which makes it difficult to get a decoder into any engine.
You should find an opportunity to listen to sound engines. Some don't like them, but many of us do. Right now, the physical size of the speakers makes sound in N-gauge a less rewarding experience than in HO. If you find that you really like sound engines, then that may be a factor in your HO vs. N decision.
DISCLAIMERS: I model in HO, and I like sound engines. And to those who say "DCC is the best thing since sliced bread," well, if it came down to it, I'd buy a bread knife rather than give up my DCC system.
It takes an iron man to play with a toy iron horse.
I am gathering information. I am returning after 10 years or so. I had a 12x12 N scale DC layout that had to be taken down. I started with HO 4x8. Dilemma: I have equal amounts of equipment for both scales with about 15 engines for each. From the perspective of a beginner DCC which scale would be easier or at least more satisfying to use DCC? I am guessing that there may be more room in an HO engine for decoders. Space is always an issue but I was thinking of just making a 2x4 diorama in whichever scale I decide on just to get my feet wet. Any thoughts???