What he needs is a switch like STSHK11-3P. This is an enclosed *three-*pole double-throw center-off switch; he can wire the hot side of the power to the throttle equipment to the third pole to guarantee the power switches along with the track. (Or use relays or a switched outlet…)
And you get to re-live a (small) bit of Hollywood history from the movie “Young Frankenstein.” Or is it “Fran - ken - steeeeen”?
RHB
Well, then, my name is pronounced eyegore.
And here I thought it was *‘Frahn-*ken-steeeeen’
They make light-switch covers that give you a better James Whale flavor, although not with the “improved” version of the idea I used in college, which played the sound of huge contacts smashing closed or open and the crackle of electricity when the fake switch was thrown. You could do that with a greeting-card-size sound chip today…
Walk this way!
If you hit up some antique markets you probably will eventually find a really big version of the knife switch, not that relatively puny plastic one they sell today.
–Randy
The kind that could …er… “wake the dead”? (Sorry, I couldn’t resist. And I thought it was hilarious that even before my above Frankenstein reply cleared customs several others of you were riffing on the Mel Brooks classic.)
We use two plugs and one outlet on our club layout. One plug connected to DCC power the other connected to DC power. We just plug the one we want to run with into the outlet that is connected to the track bus. Simple and it keeps us from inadvertantly knocking a switch to the worng position. Anderson Powerpoles are our choice of connectors.
Martin Myers
Some perhaps useful observations from the ham community on Anderson Powerpole connectors in the model-railroading size range:
We’ve been using PowerPole connectors on the club modular layout for at least 10 years now. That’s many cycles of connection and disconnection, and as far as I am aware of, none have ever needed repalcement. Since I need to have a moveable section to get past my furance and water heater, I intend on using them to disconnect the power bus when moving the section. It’s not like a duckunder liftout where it needs to be constantly accessed, so no sense in making some complex automatic contact system.
If you’re not going to use the mad scientist knife switch, then I’d definitely go with the plug method which is also about as foolproof as it gets - can’t plug 2 things into the same socket, so only the DC or the DCC system could ever be plugged in at any given time.
–Randy
Glad you found your thread. I was concerned that when it was moved to the DCC/Electronics section we might lose you forever.
[#welcome]
If you feel like it, pop on over to the General Discussion section and tell us about your layout and/or your modelling ambitions.
Glad you are here.
-Kevin
Thanks for the further ideas about plugs, guys. That might be the way I go, much as I’d like to throw that big crackly switch and laugh maniacally.
But now another worry arises. I’m seeing videos and articles that say that the way I wire my layout depends on whether I’m running DC or DCC. Yet this very thread is about just using one wiring scheme on the layout and simply throwing a switch between power sources. Is this one of those things where absolute best practices would dictate differnet DCC wiring, but reg’lar ol’ DC wiring will be fine? Or is there some real imperative to wire according to power source? I’m confused now. Opinions and small rants welcome.
Thanks again, in advance.
-Matt
It can potentially get complicated if you want multiple cabs ont he DC side so you can run multiple trains, because thent he DCC has to feed into the cab control wiring, and any scheme that simply makes the DCC an extra cab means that in one block you can have it set to DCC and in the next block set to one of the DC cabs and poof goes the magic smoke if you run past the joiners.
If you just want to switch power off in sidings so you can park locos while running a different one in DC, you can put your DC/DCC transfer switch in front of that with no problem. Being able to isolate sections of the layout by cutting power can be helpful in DCC troubleshooting as well.
For me, best practices wiring in DC is two wires to every rail - no common rail. Which also happens to be best practices with DCC wiring. Atlas track plans and some people feel common rail is better or sufficient for DC, but I never wired a DC layout like that, I always gapped both rails and ran 2 wires to each block. So doing DCC is not really different.
–Randy
If the layout is wired for multiple cab DC block control the only sensible way to operate in DCC mode is to disconnect BOTH (or ALL) DC cabs from the layout before powering ANY of the layout with DCC power.
Then arrange the block switches and cab power connections so that ALL the red pole (or white or whatever colour you chose) rails are powered from one side of the DCC power booster and all the black pole rails are powered from the other side.
If you used common rail then you need to make sure that all the common rail powered rails are connected only to the same side of the DCC power unit. Common rail is a bit of a misleading misnomer. Common rail wiring can be used for DCC very easily.
The difficulties arise when the wiring is set up for more than one DC powerpack (multiple cabs) to be connected through the common rail. DCC will not like that at all. You need to remove those connections from the several DC powerpacks when you switch over to DCC track power. You, in effect, connect each of the common rail power feeds in parallel to the one side of the DCC power booster. I assume only one booster. For more than one booster you must create double isolated power districts, much like blocks but with no common rail power.
Multiple DCC boosters are not connected up in the same way as common rail DC powerpacks may be. Two wire bus for DCC is electrically the same as DC common rail wiring. But, don’t try to add in a second booster with just a two wire bus, then you need double isolated blocks (power districts in DCC speak)
If you are wiring multiple cab block control DC make sure you have one of each pair of power wires connected to the same side of every block (common rail wiring does that). The other side of rail power should be connected to the other one of the wire pair (this will be through your block power control switches). Running that one side through a set of standard SPDT block switches makes no difference as you then just select one Cab
When Randy and I started his NORFOLK SOUTHERN N scale layout, the intention was to switch the layout over to “Command Control” when that became practical in N scale. We started the layout in 1992 I believe.
The layout was wired for three-cab mainline DC operation, and a fourth cab for the main yard. All electrical blocks could be controlled by “Cab A”.
When the time came to switch the layout to command control, all blocks would be set to Cab A with the power turned on, and the command control station would be hooked to the Cab A input. All other power packs would be removed.
So, you can build a layout for DC operation, then if it is designed properly, it can be converted to DCC easily in the future. It just takes some planning.
Typically, a layout that is designed from the Get-Go for DCC will have much simpler wiring from the beginning.
-Kevin
Thanks guys,
It will take me a while to reread and absorb all this. There seem to be myriad factors, each one affecting everything else, so how about we start with one simpler question: would running bus wires around under the entire layout to serve feeder wires from above be a good starting point for both DC and DCC, no matter how many locos I want to run in DC or DCC?
I have already drilled holes for bus wiring in the crossbeams that span L-girder to L-girder, just because I thought I’d be wanting to add bus wires. Now I’m not sure what I need, but now would be the time to do that.
I don’t envision running more than one train on my mainline at a time in DC, and I don’t have room for a yard, but I have some industry spurs so to answer Randy’s question, it would be nice to be able to do a little local switching - or park locos – on a long spur while running a longer train on the mainline, so I can see where isolating a few blocks would be useful (if, Randy, I understood your suggestion correctly). And I assume that’s what LastSpikeMike meant by “multiple cab DC block control”.
And I think I’m going to use the single-plug method of switching from DC to DCC that was mentioned earlier. I posted a rough of my layout plan earlier today on the General form and it’s been moved to the Layouts forum if that helps.
I had thought this was going to be easier to understand. 
Thanks again,
-Matt
Question… is it your intention to eventually convert to DCC?
This is my system to decide whether or not DCC is right for you… ask yourself these three quesitons:
-
Do you understand DC wiring well enough to install and troubleshoot it without help?
-
Do you already own a substantial number of DC locomotives?
-
Can you live without sound?
Unless you can answer “YES” to ALL THREE questions, you should plan to switch over to DCC.
So, if you will eventually switch to DCC, I would suggest you wire the layout for one DC cab, and just run one train at a time. Install SPST on/off switches on any spur or other track where you will want to park a locomotive/train.
Then when you switch to DCC, you will most likely just need to hook up the DCC system to where the DC power pack was, turn all the switches on, and you should be good to go.
-Kevin
Yes. Run a pair of bus wires under every piece of track. Don’t string it tight, leave some slack to allow modification in future.
18 gauge is big enough for most home layouts. Up to 14 gauge would not be overkill.
You’ll want to connect power feeders at fairly frequent intervals to connect power in addition to the conduction at rail joiners. Duplicating the path of the rails with two bus wires accomplishes that.
That’s all you need to get started.
For future flexibility you can modify this simple plan as you wire the layout but you don’t need to. The modifications can be done at any time quite easily.
If you have places in your layout where you might want to create power districts in future it may help to put in a connector of some sort. A short terminal strip using screw fasteners works well. Anywhere you may want to dismantle the benchwork it can help to have a connector installed while you run your two wire bus. The bus is connected across the terminal strip. There are two types of terminal strip. The one you should prefer creates a bus for each wire allowing you add a second or third power wire to some other rail. The other type is just a convenient point to cut the bus into sections that can be disconnected.
Two wires are enough for both DC and DCC until you want to install power districts or block control. For those you’ll want to add wiring back to a more central location. All that can be added later.
Guys, thank you again. This very specific, focused input is helping.
Mike, it occurs to me to ask how I would lay a single loop of bus wire (is it a loop?) under every piece of track when the layout is actually a folded dogbone.
I’m assuming this means just going around the perimeter of the layout underneath. It’s basically a fat L but the loop folds under itself. I wouldn’t “follow” the tracks would I?
Kevin, your Bridgemaster’s Questions Three helped a lot.
Yes, I can see myself converting entirely to DCC someday. I already have the NCE Power Cab Starter Set and one wonderful SP&S RS-3 loco – Atlas YB with DCC added, a real sweetie – but I also have several old DC locos (not zillions) and I like them. I can live without sound. But I DO NOT have an intuitive understanding of electronics and I get confused easily. I’m not sure that “without help” is important; if I’ve learned anything in life it’s that I’m not going far without asking for and accepting help from others. Still, your practical, reco
What about a DC layout with electrically isolated blocks? (DPDT to every block)
Same as SPDT. You just select the same “side” for all the block control switches. In fact those who are not fans of common rail would be doing this to run DCC voltage to the whole DC layout. You don’t need blocks for DCC so you just set all the DPDT or SPDT switches and leave 'em permanently.
Sorry for the confusion about “every piece of track”. What I actually meant is run enough two wire bus to allow one bus wire to connect to every piece of rail on one side and the other wire to the other rail, throughout. Some places you just run feeders further out from the main bus, other places you run secondary bus pairs out to where you need them.
My understanding is you do not create any loops in your bus wires. You generally run one direction from close to the center of your track layout and the other direction so you have one pair of bus wires with the booster connected close to the middle of the run, ideally. That minimizes any voltage drop due to length of run. No loops though. Branches only.
Others more knowledgable than me can advise about open “ends” to the length of each run. There is some suggestion that some DCC systems need an “end” to a pair of bus wires. Not sure what that means. Others say the bus wires should be separated by a distance or loosely twisted around each other to reduce induced radio interference. I don’t think either is a worry for the average sized home layout.