By using a switch you can change over to run your dc loco’s and still use your transformer, and then switch back to run your DCC equiped loco’s using your DCC throttle. I’m currently in the process of updating to DCC but I have several Roundhouse old kit built locos that I don’t want to put on a shelf…any suggestions would be appreciated
You can do that with any system. Simply install a double pole, double throw switch (DPDT) with DCC on one set of legs and DC on the other. The common wires go to the track. It’s very simple but you have to use caution not to leave some DC loco’s on the track when DCC is present. Some can be damaged. Most DCC loco’s however will work fine on DC.
I personally feel this is a recipe for disaster, forget to flip that switch just once and if I am not mistaken you’ll fry every decoder on every engine on the layout unless you have it on a switched dead track. What it comes down to is just extra work for what? so you can still run a couple of old dc engines, well I am of the belief that in the hands of the right person there is not a dc locomotive in existence that not be converted to dcc. Sure some are a sight more work then others and it’s definitely not as simple as a plug n play application.but it can be done none the less. So why complicate your life with running both dc and dcc. If funds are tight which they are for most of us just simply shelf the locomotives that need to be converted and do them one at a time or until the funds are available. Until I started doing my own dcc conversions I noticed that guys that did would give you some what of a discount if you changed over a bunch at a time.
For me the greatest benefit of dcc is it’s simplicity when it comes to wiring, no more block and endless miles of wire under your layout, it most definably makes for a much simpler, cleaner installation which results in better reliability. I think it’s biggest downfall if you want to call it that is the Vail of mystery or fear of the unknown so to speak.
Not at all, if a DPDT center off switch is used at the main power feed to the layout, so either the entire layout is DC or the entire layotu is DCC, it’s quite safe. Only the old cheapy SOundtraxx decoders and maybe some from the early days of DCC can’t take DC, and only a loco with a coreless can motor will fry on DCC without a decoder, at least in a relatively short period of time.
In fact, this is the ONLY way you should even attempt to do something like that. Wiring one block of a block-wired DC layout to the DCC system so that individual blocks can be either DC or DCC - now THAT is asking to fry stuff - decoders, the DCC booster - all sorts of bad things can happen if a loco bridges the gap between a DC and DCC block. Do NOT do this.
–Randy
When I came back to the hobby 6 years ago, I had a number of old DC engines, and I had a similar plan of a dual-mode layout with a toggle switch between them. When I ran my first DCC engine, though, I disconnected the DC power pack and never put it back.
DCC is so much better that you will likely do the same. Put decoders in those old engines. Once you’re fully up and running with DCC, you’ll understand.
That’s a commonly held misconception. Unless the DCC loco is a very old type that doesn’t have a dual mode decoder having it on a DC powered track won’t hurt it. All the decoders I’ve used are dual mode and have no problem whatsoever with my DC powered cleaning brush. A loco with a dual mode decoder will run just fine albeit a bit slow on a DC track unless the decoder has been switched to DCC only in which case it will just sit there and do nothing.
I do this all the time on my layout and the only problem I have encountered is forgetting to program a decoder equipped loco to run on DCC only and having it move in error when operating in DC. None of my locos or decoders have suffered any damage all though DC locos do buzz horribly if the block they are in is not isolated when using DCC.
Yeah, some DC motors won’t handle the DCC pulse well and can overheat. It just takes some basic precautions when running but nothing show stopping.
Good Luck.
You’ll be running DCC before you know it.
be a little slower… 
John