On my last layout (HO) I built for DC. I ran blocks using plastic rail joiners on both the + and the - rails about every 36". It ran well. Then I attended our annual local Train Show and came home with Digitrax Super Empire Builder. I was impressed by the DCC but did not master the CV stuff but still working on it. Anyway, I'm building a new layout and was told that I don't need to isolate the blocks with the plastic rail joiners. They said just run feeder wires every 36" like my last layout. And then I talked to someone at my LHS (the only one we got, HobbytownMSRP) and they said to isolate the blocks just in case I want to use a block detection system. So, I would really apperciate some advice/answers...Thank You.
Feeders every 36" is a good idea. Insulated joiners every 36" is kind of overkill, your detection blocks will need to be at least as long as your longest train, in most cases. Wire it all up with no insulated joiners - you can cut block detection gaps after the fact with a cutoff wheel in a Dremel. Unless you already know exactly where your detection blocks will be.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
If you already have a well blocked and reliable layout system, you could convert it to a detection layout in DCC by simply linking two or more consecutive blocks with a sub-bus. At the same time, wire 1156 auto tail-light bulbs in series into one wire of the sub-bus pair.
Basically, as a layout grows, including in complexity, you are well advised to use a main bus, and have several sub-buses providing an electrical base for the feeders necessary for one block or district. But, as Randy says, you don't have to change much...leave the plastic joiners. Just link the adjacent feeders for two or more sections of fed rail to a sub-bus. Eventually you have your fully protected and manageable DCC system needing only a hook-up to your base station.
-Crandell
I agree with Crandell (Selector) that it's a good idea to keep the blocks, and just wire them together at the bus terminals. I also agree with Randy that 36" blocks are gross overkill unless you run subway trains on rush-hour headways with working ATS.
My own blocks range in length from about 1 normal train length plus a foot to half the distance to the next town. I currently run analog DC, MZL system, but if I was planning for DCC I wouldn't change that.
The idea of wiring 1156 bulbs in series with your power feeds is a valid one, even for analog DC. So is the idea of using terminal strips or blocks where the wire to each rail section can be isolated by loosening one screw (or nut, in my case) and disconnecting it. Having that capability reduces short-chasing from a bear to a small squirrel. My terminal strips are all at the table (or shelf) edge, just inside the fascia line, so there's no need to get under the layout with a flashlight to work on the electricals.
I don't think that wiring is anybody's favorite thing. Do your best to keep it simple, neat and accessible.
Chuck (Modeling Central Japan in September, 1964)