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DCC wiring

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DCC wiring
Posted by DR. Anatomy on Monday, February 8, 2010 9:17 AM

My layout currently uses blocks in order to operate 2 trains at the same time on the same track. I am switching to a DCC system. What wiring is needed to accomplish this task? Do I need to wire just one section of track or at various sections?

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Posted by jeffrey-wimberly on Monday, February 8, 2010 10:33 AM

 Just disconnect your DC supply and connect the DCC system. Turn all your blocks on. That's it.

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Posted by cliffsrr on Monday, February 8, 2010 10:41 AM

When I switched to DCC, I figured I needed a larger feed to all the layout. I wish now that I had done just what Jeffery suggested. With all your blocks on switchs that can be turned off,  finding a bad short or problem can easily be traced to one block. Sure saves a lot of time!

Cliff

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Posted by Vail and Southwestern RR on Monday, February 8, 2010 11:53 AM
I would do as suggested, and then do the "quarter test".  Turn the DCC system on, and place a quarter across the rails at various places around the layout.  If the system detects the short, and shuts down, your wiring is sufficient.  If not, you'll have to beef it up a bit.

Jeff But it's a dry heat!

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Posted by cacole on Monday, February 8, 2010 2:07 PM

There's not much need to do a quarter test on a layout that is running okay on DC block control when you switch to DCC, because nothing in the wiring is being changed.  The quarter test proves nothing except that your DCC system's internal circuit breaker is functioning properly.  If there was a problem with the wiring, trains would't have run properly on DC block control, either.

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Posted by Vail and Southwestern RR on Monday, February 8, 2010 4:03 PM

cacole

There's not much need to do a quarter test on a layout that is running okay on DC block control when you switch to DCC, because nothing in the wiring is being changed.  The quarter test proves nothing except that your DCC system's internal circuit breaker is functioning properly.  If there was a problem with the wiring, trains would't have run properly on DC block control, either.

 

I disagree.  The quarter test verifies that the wiring to every part of the layout is sufficient to allow a short circuit to be detected.  Wiring that works perfectly well on DC may not be adequate for this.  Usually it will be, but it doesn't hurt to be sure.

Jeff But it's a dry heat!

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Posted by locoi1sa on Monday, February 8, 2010 4:31 PM

cacole
There's not much need to do a quarter test on a layout that is running okay on DC block control when you switch to DCC, because nothing in the wiring is being changed. 

 

   The quarter test is very important. There are a lot of old DC block controlled layouts that are wired with 18 to 20 Ga wire out there. Do you really want 5 amps of current going through 20 feet of 20 Ga. wire?  Shutting down the booster in a blink of an eye is important not only for your decoders but also for your wiring and track. The less important reason for a quarter test is if the wiring is not solid enough than your digital signal would be corrupted and you will have control problems. The control packets being sent to the decoder would be ignored and the decoder will follow its last known good packet. Just what you want not to happen when backing down that siding or running behind the first section of a train.

         Pete

 I pray every day I break even, Cause I can really use the money!

 I started with nothing and still have most of it left!

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Posted by DR. Anatomy on Tuesday, February 9, 2010 12:52 PM

Thank you all that responded to my question. Perhaps I should have prefaced my question with the following statement - I had to redo my layeout do to a flooded basement. I am using the same plan with the exception that I want to use DCC instaed off DC. Therefore do I need blocks and if not how many electrical connections do I need to make with the track and my DCC system?

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Posted by maxman on Tuesday, February 9, 2010 1:10 PM

DR. Anatomy
I had to redo my layeout do to a flooded basement.

All of the above answers assumed that you were using your existing control panels and their associated block toggle switches.  Have all of these been removed during the redo?

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Posted by DR. Anatomy on Tuesday, February 9, 2010 3:58 PM

Yes. I don't want to use the blocks if I can help it.

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Posted by Vail and Southwestern RR on Tuesday, February 9, 2010 4:12 PM

Well, that's different then!

You don't need to use blocks, though having several sections that you can isolate can be useful for debugging.  In general the plan is to run a fairly heavy bus (14 or 16 gauge) from the command station  around the layout.  From that drop short feeders (18 or 20 gauge, or even smaller, as long as they are short) to the rails at six foot intervals, or so.  One "rule of thumb" is to have a feeder on every section of track that isn't soldered to a track that has a feeder on it.  There are about as many opinions on how many feeders should be run as there are people running feeders.

Jeff But it's a dry heat!

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Posted by maxman on Tuesday, February 9, 2010 4:31 PM

DR. Anatomy

Yes. I don't want to use the blocks if I can help it.

Okay, can we assume that you still have the track gapped as it originally was?

If this is the case, what are the approximate block lengths?  Just the longer ones, not the little short ones that you might have used in an engine terminal.  If you're talking about the long ones being in the 6 to 10 foot range, and all the joints are soldered, you can probably get away with one feeder in the middle.  If your existing block power feeder locations were located this way, you can just connect from your DCC bus to these points.

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Posted by richg1998 on Tuesday, February 9, 2010 4:40 PM

With a few blocks this might not be an issue.

Our club with fourteen blocks and a couple reversing loops has been an issue as are some passing sidings so we are completely re-wiring all the block drops to a buss system with heavier wire than was originally used with the DC blocks when the layout was wired nearly thirty years ago. We run DCC and sound with lighted passenger cars and sometimes a couple three sound engine consists.

The layout is still common rail with the handlaid tracks sections soldered within the blocks.

Rich

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Posted by locoi1sa on Tuesday, February 9, 2010 5:04 PM

   Here is a couple links for you.

 http://www.wiringfordcc.com/track.htm

http://www.members.optusnet.com.au/nswmn2/DCC.htm

   Both are very good with a lot of information.

       Pete

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 I started with nothing and still have most of it left!

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Posted by DR. Anatomy on Wednesday, February 10, 2010 4:32 PM

What if I don't use the blocks? My original layout got wet therefore I am starting from scratch and rebuilding the same layout and would like to eliminate the blocks. Any wise words of wisdom as to how to wire the system? Electricity isn't my cup of tea.

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Posted by jeffrey-wimberly on Wednesday, February 10, 2010 4:45 PM

 Run two 14 gauge wires (red for the right rail and black for the left other rail) under the layout so they follow the general direction of the track. These are your buss wires. Every 6 - 8 feet drill a hole beside the outside edge of each rail that big enough to allow a 20 gauge wire to through. Again, red and black. Solder the 20 gauge feeders to the outside edge of the rails and to the 14 gauge buss lines.

Running Bear, Sundown, Louisiana
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Posted by dsabourne on Thursday, February 11, 2010 2:11 PM

I have an Atlas track layout I would like to convert to DCC.  Do I need to solder all the track sections together?  Can I use Atlas Terminal Rail Joiners as the feeder wires?  I understand that similar to the original author I have a DC block system, I will like need to revise some wiring (heavier gauge) and update the one common wire I had too.  Also should one DCC connection work to power two 4x8 oval tracks and couple of short sidings?

Thanks,

David

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Posted by locoi1sa on Thursday, February 11, 2010 3:27 PM

 David.

  You do not half to solder all the sections together. If you solder them together in 3 to 4 foot sections and leave the rest unsoldered for expansion and contraction would be fine.

  Do NOT use terminal joiners unless you plan to solder them to the rails.

  One DCC buss would be fine. I posted a couple links earlier in this thread that is really helpful to new DCC people.  The one from Allan Gartner is super and pretty much like the bible of DCC wiring. Just remember to do a quarter test. That is the determining factor if your wiring is OK.

     Pete

 I pray every day I break even, Cause I can really use the money!

 I started with nothing and still have most of it left!

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Posted by dsabourne on Thursday, February 11, 2010 3:38 PM

Pete:

 I would really like to avoid solder ... not experienced at doing this ... don't owe a solder.  Why can't I just use the terminal rail joiners as feeder wires?  Do I really need to solder track joints?

Thanks,

David

David Bourne Kitchener, Ontario
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Posted by jeffrey-wimberly on Thursday, February 11, 2010 4:06 PM

 You can use wired terminal joiners but the connections on them are not robust and can be pulled off easily. Don't be scared of soldering. It's easy to learn and is a snap once you get the hang of it. On soldering track joints, it's not really necessary that you do so but it makes a much better electrical joint and you won't have to worry about corrosion corrupting the connection later. The easiest way to solder two pieces of track together with joiners is to put a little flux into each joiner, put the sections together, touch the soldering tool to one joiner and apply the solder at the joint. The flux will pull the solder into the joint. Repeat with the next joiner. If you don't want to solder wires to the sides of the track you can solder them to the bottoms of the joiners.

Running Bear, Sundown, Louisiana
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Posted by dsabourne on Thursday, February 11, 2010 4:27 PM

Thanks Jeffrey.

Can you solder track joints already in place or do you need separate them and put a little flux as you note in each joiner and then reconnect?

My current track feeder wire is the standard Atlas wire (I believe is 20-ga?) do I need to up this to heavier gauge.  My layout is only current a 4x8 with a max of 3 trains running at any one time.

Thanks,

David

David Bourne Kitchener, Ontario
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Posted by Vail and Southwestern RR on Thursday, February 11, 2010 6:44 PM

The 20 gauge feeders themselves are fine, as long as you keep them short.

If you don't solder, you are eventually going to have issues, it's just a matter of time.

Ideally, you would separate things, and then solder.  But, if they are relatively clean, a little flux on a toothpick would probably run into the joint, and the solder would follow.  Don't buy into the idea that you need a high power iron.  What you need is a good clean tip, a little flux, and relatively fine solder.  Get it hot, hit it with the solder, and get out.

Jeff But it's a dry heat!

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Posted by jeffrey-wimberly on Thursday, February 11, 2010 7:28 PM

dsabourne

Can you solder track joints already in place or do you need separate them and put a little flux as you note in each joiner and then reconnect?

My current track feeder wire is the standard Atlas wire (I believe is 20-ga?) do I need to up this to heavier gauge.  My layout is only current a 4x8 with a max of 3 trains running at any one time.

If the track is already down and in place then just put a little flux along the outside edge of the joiner and make sure it gets on the rail too. Touch the hot solder tip to the joiner, apply the solder then move on to the next one. The wire you have should be good. If you think you need something heavier you can use 18 gauge. Anything bigger is going to be harder to hide under the ballast.

Running Bear, Sundown, Louisiana
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Dr. Frankendiesel aka Scott Running Bear
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Posted by slow train Ed on Friday, February 12, 2010 10:10 AM

when you say (short) what is short? 3 inches 18inches?? thank you for your time.

slow train Ed

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Posted by jeffrey-wimberly on Friday, February 12, 2010 11:09 AM

 Short, as in the length of feeders, should be long enough to go from the rails to the buss lines with a little slack. Who wants a bunch of taut wires?

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Posted by Texas Zepher on Friday, February 12, 2010 2:18 PM

Edit - when I wrote this I did not see the entire 2nd page of responses......   I thought I was responding to the last post on the thread. 

DR. Anatomy
What if I don't use the blocks?.... Any wise words of wisdom as to how to wire the system?

Yes,  How long is the main line of the layout?   Are we talking a 4x8 or a basement full?

1. Run a pair of power wires along under the main track.  This is called a power bus.  Wires should be 14-18 gauge depending on length.  The longer the bus needs to be, the heavier the wire (smaller gauge number) will need to be.  Personally I always twist mine, but that is not necessary.
2. Connect the wires of the power bus to the output of the DCC control unit.  Test to make certain power is getting to the end.
3. Every 6 feet or so run a set of wires from the power bus to the track.  These are called feeder wires.  This will mean that a locomotive will never be more than 3 feet (1/2 the distance between feeders) from power.  Feeder wires can be lighter wire (like 20-22 gauge). 
4. If the power bus is going to be longer than 30 feet there could be issues, so then several things can be done:
     A.  Move the DCC controller unit to the center of the bus (making two shorter segments on each end).
     B.  break it into two put a gap in the rails, and add a DCC power block controller unit (Digitrax PM42, CVP zonemaster, etc.).
     C.  break it into two put a gap in the rails, and add a DCC booster unit.
     D.  add a terminating resistor.
     E.  combinations of the above.

Don't make it harder than it is.  It is very simple.

 Another comment.  I normally use stranded wire for the bus and solid for the feeders.

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Posted by rrinker on Friday, February 12, 2010 6:58 PM

 That's what I do - except I have feeders soldered to EVERY joiner on the layout. Now here's why you should get a soldering iron and learn: for the price of 1 pair of terminal joiners, you can buy a whole pack (24 pairs) or regualr metal joiners, and solder your own wires to them. You don't do this on the layout or in any other awkward position - I build up a supply sitting at my workbench.

                                    --Randy

 


Modeling the Reading Railroad in the 1950's

 

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Posted by selector on Friday, February 12, 2010 9:35 PM

David, to back up just a bit and take a breath ('cuz I can see yer turnin' blue...), here is the scoop:  the metal joiners and soldered wires, called terminal joiners, are a great idea, but they only solve part of the overall problem with joiners.  I'll explain...and this is where you take another breath. Smile

The metals in the rails and the metals in the joiners are not the same.  Basic metallurgy/chemistry will tell you that it means ion exchange over time.  Add bits of grit, dirt, flexing joints as the heavy locomotives pass overhead time and time again, and the corrosion of the ion exchange....you can see that joiners are going to fail.  Maybe two years out, but more likely six months out...if all our experiences count and we add them up.  Joiners left by themselves just don't hold up well over time...period.

Feeding the joiners is a good idea...great in fact, but if the rest of the joiner surface mated to the rail feet is corroded and not making good contact, of what use are those nifty soldered wires?  They aren't!  So most of us eventually capitulate, pay homage to the rail gods, and agree that we mere mortals will have to find a more robust solution.  What we do is solder the joiners to the rails, and this is done when the joint is already made and the rails are oriented and fixed into place with track nails or caulking...whatever.

You don't need to solder every joiner.  Instead, do every second joiner.  That way, both lengths of track going either direction from that joint are positively powered.  You can let the far next joiners over in each direction slide and provide your tracks with heat expansion and humidity expansion if you have fluctuations in those. They don't need to provide continuity because those middle soldered joiners are doing that for you.

Yes, absolutely, you will get a soldering iron, burn your fingers at least three times over the first year, and you will learn how to do it...I did.  And you'll actually get to like it....I did. Big Smile  In fact, there wasn't much of anything I knew about the hobby just five years ago, but I do pretty well now.  I have completed two layouts, the second with spline roadbed and soldering and wiring for DCC.  Trust me, if you can start a car, you can solder. Just be sure to ask what the good equipment and materials should be.

-Crandell

 

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Posted by dsabourne on Saturday, February 13, 2010 12:19 AM

Thanks Crandell ... information overload  .. yes ... and I'm turning a bit blue ... but well worth the world of knowledge.  Basic metallurgy/chemistry, eh?  Its been over 20-years since 1st year chemistry in engineering school. LOL.  Don't remember doing that well in Chem Eng 101 ... I guess that is way I stuck with civil engineering instead ... airports (avator taken at LBPIA 2003), highways and international border crossings.

I have reviewed my layout plan for my simple two loop 4x8 layout and will probably layout a bus loop of 16-gauge under the tracks and place two feeders from each rail on each loop from the bus.  The length between feeders would then be approximately 8', which seems in order for the typical ranges I have read of 6 to 10 feet.  If I feel I need more (constant) power, I can simple add more feeders.  However, I currently run the layout with 18-blocks and common rail, and don't have any issues, with slow areas.

With the recommendations herein and in hommage to the rail gods ... I guess I have to break down and procure a solder and take a tack at it.  I may still try to work with terminal joiners as I have lots left over after I dissemble the obsolete block system.  However, I will likely follow advise and also solder some the track joiners, ie everyother one.  One question, though, I am to understand that you have feeders to each section of soldered together track?

Hopefully, I'm on the right track.

David Bourne, P.Eng.

David Bourne Kitchener, Ontario
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Posted by dsabourne on Saturday, February 13, 2010 10:14 PM

Well I have do some more internet reading and You Tubing ... to learn that flux and solder are not the same thing ... I thought that flux was another name for the liquid solder.

Another question, though, is it seems everyone talks about a 5A current ... however, I am looking at Digitrax Zephyr is its output 5A or 2.5A?  Voltage output is 12.8V.  I am trying to complete my wire requirement calculations.

R = V(wiredrop) / I (boostercurrent)

Thanks,

David

David Bourne Kitchener, Ontario

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