Thanks all for the responses and ideas. Finally getting serious on this part of the new layout and had one more question. I run Lionchief and DCS locos. In configuring the switches like Rod and Steve show above, is there any "best practice" or pitfall to avoid messing up the DCS signal? On my previous layout, I used buss wiring and did not have a yard- never had a DCS issue. On this one I plan to use the proverbial star approach so the yard, siding, or turntable switches will be a extensions of a block or added to a track connection. Any thoughts are appreciated.
Take heart, your DCS signal will likely be just fine. My layout was initially built back in '98, and it was not wired with any regard to future DCS parameters, because DCS was unheard of at the time. My mainline track runs are all switched through Atlas 215 4 pole double throw blocks. And the yards and turntable are all switched using 12 position rotary switches. My mainline blocks are all interconnected center rails; no isolation points at all. In some cases there are at least two or three track power drops wired from the same supply run; an absolute DCS no-no. No thought was given to star wiring. I would have used MTH 12 and 24 circuit block terminal boards, but of course they didn't exist at the time either.
When I first added TMCC and DCS in about 2008, it was with an I3a rev TIU. Initially I had some signal issues in a few places, but by adding so-called "magic bulbs" to the TIU outputs those mostly went away. The other problem that arose was some sidings where I had used connector #3 of UCS tracks to power the siding. Some of these sidings had DCS issues, I believe because of the coupler coil in the UCS. These problems mostly went away by adding a 260 lit bumper to the siding. If building from scratch today, I would omit all of the siding UCS's; simply not needed. Anyway the layout is operating just the same today 13 years later, even better, likely because of replacing the original TIU with a rev L. If I had it to do over, there would be some changes for sure, but mostly it works quite well. Last time I did a signal check around the layout there were a few areas of 4-6 strength, but most were in the 8-10 range. Generally any signal above about 3 seems to provide pretty reliable operation.
Hope that helps, Rod