DCC Layouts

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DCC, a second opinion

So. Where to now? At the a recent show several questions were posed about the wiring needed for a DCC layout. Some of the answers are here. We will leave decoding your locomotive for another time.

Under the table wiring

My advice depends on your situation. If you already have a layout then just set your mainline block switches on and forget about it. You want to keep all analog engines on the layout on sidings that are “off” for the time being. When all of the engines on the layout are DCC then set all of your block switches on. You really don’t even need blocks anymore...almost...read on. If you are planning or have started construction but haven’t put any wires in other than the “feeders” from the track to under the table then just use 12 gauge solid house wire for the track busses. Inside type insulation is preferable and for the most part, 14 gauge appliance cord would be overkill. You are looking for lower cost here. Actually, 18 gauge (some speaker wire) would work for most situations. Use 22 or 24 gauge (telephone wire) as feeders from the rail and put in one set of feeders for each block. My blocks are not more than 10 feet apart even on a double track main.

Speaking of blocks

No, you don’t want to remove blocks. They are as important as ever if you want to progress into occupancy detection. You may also want to have blocks for highway crossing signals or other wayside train actuated accessories. Blocking is also needed for transponding so…keep them blocks. Just turn all the block switches to on or to one cab if you have cab control. You might want to think about getting rid of your panels, well, not the whole panel, just the block switches but not for sidings. There may be a day when you want to park an analog engine and this is where you turn the switch to off.


Maybe some detection lights, maybe some block switches, maybe a turnout button or two, maybe nothing more than a track reference guide. Panels are questionable now. If you go all out with DCC your panels really would be just flat LCD panels with CTC driven from a computer. You might even use touch control or certainly mouse control for the panel. There is really very little desire to spend a lot of time in creating and wiring panels once you start to use DCC.

Reversing Loops

Sorry, you still are going to have reversing loops. But the good news is that you don’t have to mess with a manual switch anymore. Cheap automatic relays are available for reversing loops from MRC (500-AD520/TB$30.79). More complicated ones (handles up to four loops) are available from Digitrax (PM42/TB$63.96).


There has quite a lot written about the “DCC friendly” turnout. The truth is that any “analog friendly” is also “DCC friendly”. If you have a turnout that can cause a short at the frog in analog then it will cause a short at the frog in DCC. When we used block control we had to think more about where we ran our trains. We were always concerned about the power in the next block and the right orientation of the turnouts. When you are running DCC, because you now are the engineer and not dispatcher, you tend to overlook “running a switch” (coming in from a diverging point when the turnout is thrown against you). At the very least, you will derail any light freight cars. At most you will short out your controller and will get the nasty beeps until you throw the turnout. In rare cases (leaving your train running unattended for long periods of time) you can have a set of wheels hang up on a frog or points and cause a protracted short. Left unattended, this can cause heat and a severe meltdown.

Occupancy detection

Blocking your layout is one method of occupancy detection. Digitrax makes a 16 block detection card (BDL162/TB$100.00). This is current detection. You must flow one rail through the card. This means that 16 blocks have to “home” at this card. Well, so much for “busses”. Because of this, I found multicolored 12 gauge stranded wire at Home Depot in 500 ft. spools. You may also want to investigate infrared or light detection at certain critical points (diamonds or main turnouts). This will require a non commercial circuit. (See the Train Buddy!)


We have discussed the starting points for automation; blocks and occupancy are necessary. Signaling, at least, is the next major hurdle. Once block detection is in place, setting signals and making them work accurately is not that tough. It may be though, that you want to do a centralized signaling system with dispatcher control as it is in some older prototypes. This would require some of the newest electronics (SE8C from Digitrax) and quite a bit of wiring. A typical SE8C has connections for over 100 wires. The next leap into automation would be transponding. This means that not only can you tell that a block is occupied but by which piece of equipment by the number. Relating this to the airline industry it is how the air traffic controllers see the number of the plane showing up on their radar. For computerized train control (CTC) you can program, using WinLok, your display to show the number of the engine in a block. This is the top end of automation currently in the business. Transponding is still out of reach for most but is certainly available and prototypical for those modeling today’s railroads.


For the most part, I spend a lot of time just planning where to mount cards, what to number things, and keeping track of the numbers. Sometimes the bookwork is daunting. Yet, if you want to have an “advanced” DCC layout then this is one of the challenges that you should expect to deal with. It all comes back to challenges. Do you like them or not. If not, get us to help you. We like challenges.

Contact us at 919-562-4378 or e-mail:info@trainbuddy.com

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This page was last updated: 2015-06-21