I have a small, table top HO layout with six blocks with common ground wiring and a separately wired (X and Y) reversing section. I am contemplating converting the layout to DCC. Mike Polgrove’s 01/10 DCC Corner in Model Railroader, “Tips to Convert a layout to DCC” contains the following caution: “As long as your layout’s electrical blocks don’t use common ground wiring, it’s possible to simply connect a DCC booster in place one of your DC throttles.” This implies, but does not say, that one can’t use common ground wiring with DCC.
However, in the Model Railroader down loaded “Information Station” set of articles called “Getting Started with DCC” (which I recently acquired), there is an article by Cody Grivno entitled “Digital Command Control in an Evening” showing wiring of an N Scale layout similar in arrangement to mine that appears to use common ground wiring.
I have used 20 ga. wire throughout my 7’ x 3’ layout, and, as indicated above, it has a reversing section, controlled as a separate block through a DPDT switch, connecting two sides of the outside loop. Based on the Grivno article, it looks to me like I could hook up a DCC command station in place of my DC Throttle Control, use the existing reversing section as a programming track (as long as all other blocks are set to “off”) and sail into DCC land very easily, so long as I don’t use more than two locos. But still there’s that caution from Mike Polsgrove.
And, I’d like to work an auto reverser into that reversing section, but it connects to two different blocks, one at each end. How would I wire in an auto reverser (or perhaps it takes two of them)?
What do those of you with more DCC conversion experience than I have to recommend ?
Thanks for all your help,
EdwardjIII
Edwardjill
Welcome to the Forums. [swg]
With a layout as small as the one you have, you should not have a problem converting it by just removing the old DC power pack and connecting the new DCC system, per Cody Grivno. If you are using the aux outputs of your DC power pack, you may have to keep it connected to the accessories because the DCC system does not have an aux output for them. You don’t have a large layout that would need more than one booster, so you will be OK. If you wanted to divide the layout in to two or more power districts, then you would have trouble with the common rail wiring you now have. However, your layout does not need more power districts. Your current 20 gauge wire is also OK for this layout.
As for the reversing sections, leave the DPDT reversing switch in place until you become comfortable with the way the DCC system is operating. Operate it the way you are doing now and everything should be OK. If you do forget, the DCC booster will see a short and shut down. Once the short is cleared, it will come back up. However, I would NOT recommend using the reversing section(s) as the programming track. I would recommend that you add a special track for programming. It doesn’t really have to be ON the layout, but can be close to it. Different DCC systems use different types of connections for the programming track, so you will have to see what the manual says.
When you are ready to add an auto reverser, just put it in place of the DPDT switch. Two wires in and two wires out, just like the DPDT switch. They do have an input side and output side, so you will need to determine the INPUT wires on the switch now, and use them for the input to the auto reverser. Now, not all auto reversers will work with beginner DCC systems because some take more current to trip than others. This is something that you will also need to research and ask questions about when you dec
If your common rail DC wiring has just 1 connection to the common rail, you’ll want to add more feeders on the common side. Otherwise, there’s no issue hooking up a single DCC system to the layout as-is. There are some issues with common rail wiring if you go to add block detection or end up adding multiple boosters, but with a signle booster everythign will be fine.
–Randy
Gandydancer19,
Thanks for the very complete and informative response to my inquiry. One more question for you: Why do you advise against using my isolated reversing section as a programming track? Is it because one input to the DPDT switch which operates it is connected (at the transformer) to the common wiring that serves the rest of the layout?
Regards and thanks again,
EdwardjIII
Edward,
I cannot speak for gandydancer, so I will let him answer the question for himself.
However, I do agree wholeheartedly with his advice to use a separate isolated section of track apart from the main layout as your programming track to avoid problems. Programming engine decoders on the main DCC layout is possible and many of us do it from time to time. However, if for some reason, you forget to throw a switch to isolate the “programming track”, you can wreak havoc with other engine decoders on the main layout. It is true that an engine decoder can be “programmed on the main” but only at your own risk. Using an isolated reversing section seems safe but…
Rich
Rich has it right.
Plus, when using a reversing section as the programming track, the wiring can get complicated. Particularly if the reversing section is polarity switched by an Auto Reverser.
Plus, the switch can be forgotten and cause problems with the command station booster and programming circuit if it is not set correctly when the layout is running. I know because I have done it. I have now moved my programming track off the layout.
You can wire almost anything to do anything you want, but then if you don’t write yourself good instructions on how to use what you have designed that is not normal, you can become easily confused. When I was still working in electronics we had a saying when working designs out: KISS. Keep It Simple Sherlock.