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.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Lehigh Willie Gandydancer19, 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? EdwardjIII
Gandydancer19,
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?
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
Alton Junction
Randy,
Thanks for your advice,
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,
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
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Edwardjill
Welcome to the Forums.
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 decide what DCC system you will buy or have.
A little more about DCC auto reversing sections. When using DC, if you changed the switch under a moving train, the train would reverse directions. Thus, you generally had two switches. One to reverse the loop, and one to reverse the layout. In DCC, this does not happen. So as an example, if you have a reversing loop, only the loop would be connected to the auto reverser. You would not need to change the polarity of the main layout any more. When the train entered the loop, and the loop was not set right, the auto reverser would change the polarity of the loop to match the layout for the incoming train. When that train went to exit the same loop, the auto reverser would again change the polarity of the loop to match the layout.
Hope this helps.
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,