Thought I'd chime in here a bit late.
One of the reasons I went with Digitrax was that I had MANY engines with only a few that had DCC decoders in them, and wanted to be able to run a DC lashup simultaneously with the rest of the DCC trains.
This was a great decision, and I've never had an engine burn up or lost a DC lashup during operation or at a show.
The idea of having portions of the layout stay with their old DC wiring and route power through your Peco turnouts really sounds to me like you're asking for problems.
I bit the bullet and ripped out ALL of my old rat's nest of DC wiring after buying my Digitrax system. Before I did the ripping, wanting my layout to be down for the least amount of time, I built a small 6' long DCC test section to learn what was the best wiring for me, and to know how to wire up a programming track, and to make sure my turnouts weren't going to cause problems.
My son and I spent about two weeks learning the "ropes" of how we were gonna solder the feeders in, what type and gauge of power bus wire, sub-bus wire and feeder wire we were going to buy and use, and ordered exactly what we needed to do the job like what we decided was best for our portable, modular, growing layout.
My DC yard looked pretty simple to operate, but ya needed to know how to do it since each long siding's power was provided by the circuitry on my under-the-layout Tortoises...meaning the siding was powered when the turnouts were thrown to the siding. The power went off (so I could park engines) when the turnouts were routed for alternate routes. Each siding was gapped into two parts so that half of a siding could be powered, or the entire siding could be powered if both turnouts leading into it were thrown to that siding. This worked pretty good (so I thought) before I knew anything about DCC, and it was fun to be able to couple up to another engine sitting just on the opposite side of the gap on unpowered rails, then align the turnouts and go pick up a train with the entire lashup powered. However, LOTS of complicated wiring goin' on as well as turnout aligning and throwing!
When I decided to go DCC, I was all-the-way-IN, and wanted to not have to do the cumbersome power-the-siding-by-throwing-the-turnout trick any longer.
In other words, I wanted to run TRAINS...not run the layout.
So, I installed high-purity, 12AWG, many-strands, Red/Black Zip speaker wire as my main power buses for each of 3 power blocks (east, west, yard/industrial/branchline) with 14AWG equal quality cables (non-Zip) used as "sub-buses" to which the 22AWG solid copper track feeders (no longer than 8") would attach to. I also attached a feeder to each and every piece of powered rail on the layout, which meant a LOT of feeders because of all the gaps in the rails due to my old DC power routing/turning off scheme. All feeders were soldered to the bottoms of the rail foot after flattening, tinning and bending a 90deg. angle on to the very end of each feeder.
Additionally, after a bit of research, I decided to use genuine 3M Scotchlok Insulation Displacement Connectors (IDC's) for ALL connections that were feasible under the layout, excepting my DC accessory circuit for Tortoises and Loconet Panel power.
My layout is modular/sectional and it was going to go to about 3 shows a year being hauled in the back of my Suburban and in a big U-haul trailer in various types of weather and road conditions...and the jostling (in the past) had caused electrical problems at solder joints, and so...I wanted to use the 3M IDC's to see if they would solve that problem. In the 14 years since I re-wired my layout, I have not had a single wire-joint failure of any kind, except for a few in my DC accessory circuit with its dangly old solder joints.
I remember well plugging in my DCC power board for the first time, and running a Kato F-3 that was my first DCC decoder install, from the sand-house track located north of the east bound mainline, over several service tracks and a center siding, over the west bound mainline into my code 40 Park City Branch Yard trackage, into the old turntable access turnout and onto the turntable and engine house track...all without having to throw a single toggle switch, kill the power, select a throttle, then change throttles, or make sure my turnouts were thrown correctly to power up sidings and service tracks....I was running the ENGINE...not running the track. All I had to do was make sure the turnouts were thrown the right direction to get to my destination...so that my engine would roll over the track...not in order to supply power to that track. It was a completely new experience for me on my layout, and it was SWEET!
Then, I ran my sound-equipped Athearn Challenger through the Echo yard, back and forth...here and there...making sure everything worked (it did) and I was completely hooked.
Now when I look back at it, leaving the old DC wiring intact, routing power with power-routing points on Peco turnouts...with the attendant perpetual problems that scheme produces...is something I would NEVER advise anybody to do if they're interested in running trains, and not fiddling with the layout all the time.
With the right DCC system, you can still run your DC engines before you DCC-ize 'em...and get rid of all that old-fashioned, obsolete wiring and operating methodology that DC requires.
So, I heartily agree with both
@Dave V and
@peteski (and others) and recommend that you @CRL don't give so much importance to your DC schtuff...bite the bullet and go whole-hawg into quality DCC, with all of its attendant advantages and simplicity. I am sure that after you run your layout after rewiring it to much simpler DCC standards, that you will agree.
Cheerio!
Bob Gilmore
