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Best wiring practices for a large DCC layout?

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Best wiring practices for a large DCC layout?
Posted by Onewolf on Monday, January 05, 2015 1:20 PM

I will begin construction on my new layout within a couple of months pending completion of the detached garage/workshop we are currently building (build photo album).  I will be building a 28ft x 32ft multi level HO layout. The layout will be controlled via Digitrax DCC and is much larger and more complicated than my previous DCC layout.  I am looking for advice on DCC wiring/standards/practices from people with experience building and/or maintaining larger DCC layouts. I plan to have approx 60-80 locomotives on the layout with up to approx 40 potentially running concurrently.  There will be approx 80 turnouts driven by Tortoises and controlled via fascia toggles and/or DCC/computer control.

Thanks for any/all advice.

Modeling an HO gauge freelance version of the Union Pacific Oregon Short Line and the Utah Railway around 1957 in a world where Pirates from the Great Salt Lake founded Ogden, UT.

- Photo album of layout construction -

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Posted by Renegade1c on Tuesday, January 06, 2015 3:02 PM

Prior Planning is your best friend and from the looks of it you are trying to do just that.

A few Questions for you to consider

1. Are you planning on adding signalling in the future? I ask because it will affect how you wire the layout. 

2. Are you planning on having power districts (Circuit breakers) to divide up the layout?

As far was wiring goes I try to keep it simple. I developed my own wiring code and have it well documented. Documentation is very important because it will let you know what you did 10 years from now. 

I use 12 guage solid core wire for my main power busses. I use red and black. I use colored zip ties to distinguish the different bus wires for different blocks ( I have a full CTC signalling system)

Some people prefer stranded wire because it is easier to pull. I find it is more difficult to solder feeder wires to stranded.

For Feeders I use 22 gauge solid wire  again in red and black. I solder them to the rail and directly to the buss wires. I strip about a 3/8" section of insulation off the buss wire, wrap the feeder around about 3 times and solder it. I stagger the feeder connections by about an 2 inchs or so to prevent the uninsulated sections of the buss wires from ever touching. I use a blue wire for the frog on my turnouts. This is connected to the aux contacts of the tortoise to throw the polarity of the frog. 

I also have two accessory busses (+12 VDC and +5VDC) to power the accessories on the layout. These accessories include several Digitrax DS-64 stationary decoders, PM-42 circuit breakers, RRcirkits TC-64 (block detection circuitry), SE8C Signal decoders, Several cutout relays, 30 tortoises, and building lighting.

I use an old computer power supply that i repurposed for the accessory busses. I use green (ground), orange(+12v) and yellow (+5v) for accessory buss. I jused 16 gauge stranded wire for this (it was free). I would have prefered solid core but I will take free in this case. 

I use CAT 5 Ethernet cable for low current applications (control panels, Tortoises). I use it both in the outer casing and sometimes i strip off the outer jacket and just use the twisted pairs seperately. I use the twisted pairs to connect the Tortoise switch machines the DS-64's. I also use the CAT 5 cable to wire my control panels to the DS-64's. I don't use any special connectors. I strip the wire and use the screw terminals on the DS-64. It works out pretty well since there are four twisted pairs in the CAT 5 cables and the DS-64 has four drive circuits. 

One of the best things I did for wiring my layout was wire management. I went to the big box hardware store and picked up a few containers of plastic/nail romex cable staples. I use these to hold all the buss wiring in place. 

Wire management will be the best thing to make sure you have a clean and easy to understand layout. 

I like using the DS-64's because I too like having fascia controls (more detail on those on my website in my signature) and the abiilty for the dispatcher to also have control. 

I use digitrax and subsequently loconet to tie all the accessories together (RR circkits, Team Digital and a few others are all loconet compatible). I use a Locobuffer USB to allow computer control and to run the logic for the signalling system. 


Colorado Front Range Railroad: 
http://www.coloradofrontrangerr.com/

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Posted by gandydancer19 on Tuesday, January 06, 2015 4:38 PM

Renegade1c has covered it really well.

Elmer.

The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.

(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.

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Posted by Onewolf on Tuesday, January 06, 2015 5:03 PM

Renegade,  Thanks for the informative response.  Your website also has a lot of useful information! 

1) Do I plan to add signaling?  Let's assume YES.

2) Power Districts?  Yes.  What factors did you use to determine how to split your layout into districts?  Locomotive density?  Physical location?

Anyone else with comments/opinions are encouraged to respond. :)

Modeling an HO gauge freelance version of the Union Pacific Oregon Short Line and the Utah Railway around 1957 in a world where Pirates from the Great Salt Lake founded Ogden, UT.

- Photo album of layout construction -

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Posted by MisterBeasley on Tuesday, January 06, 2015 5:38 PM

Yes, good advice so far.  To the wiring, I would like to suggest that you develop a wiring color code and stick to it.  I have a track bus, of course, but also multiple wiring buses for street lighting and structures.

Install your wiring buses very early in the construction process.  I use an open grid frame and 2-inch pink foam for my primary layout base.  I drill and install all the bus wires before I put down the base sections.  I've kept the benchwork sections short in case I ever need to take them up, and I try to use terminal blocks where benchwork breaks occur.

Both the physical size of your layout and the number of engines you plan to run make me think that you will need more than one booster.  Think about where you'd like to divide the power districts, because your bus wires must be part of that division.

It takes an iron man to play with a toy iron horse. 

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Posted by rrinker on Tuesday, January 06, 2015 5:38 PM

 1. Label EVERYTHING

2. See #1

Keep a notebook as well with a record of where each wire goes. Use color coding when possible.

For a physically large layout, consider distributing the boosters rather than putting them all in one location with long bus runs. The shorter the bus runs, the better. Instead of a 50 foot bus run from the booster cabinet before it even connects to any feeders, run a 50 foot control bus wire and put the next booster close to the track it feeds.

If you are going to have, or evetually have, signaling and detection, plan the detection zones now. Distributed transformer detection such as the RR-CirKits BOS-8 are superior in almost every way to centralized diode drop detectors like the Digitrax BDL-168. Plan the detection zones, so the main bus can drop to a detection sub-bus for all the feeders in a given detection section. The one interconnect between the main bus and the sub bus is where the detector goes.

 Not sure how stranded bus wire can be harder to solder feeders to - it's a zillion times easier to pull around under the benchwork though, especially when you get into #12. My Ideal Stripmaster simply peels back a small section of the insulation mid-wire, and I wrap the stripped end of the feeder around it. Solder, and done. I'd posit just the opposite - with the stranded wire, if the solder doesn't soak into the strands, you haven't heated it properly and you WILL have a cold joint. Easier to visually see a good joint with stranded. The proper strip tool is worth its weight in gold, Ideal Stripmaster or the equivalent Klein, mine does #10 down to #22, and will do end strips as well as mid run strips - which is what you need to attach feeders. It does so without nicking the waire - however with stranded if you nick one strnad, no big loss. Nick the conductor of solid and you're asking for a break.

 I happen to use red and white for my bus runs, because they are readily available colors, and red and white are easy to tell apart in dim light. Plus there is some #20 solid wire in the same colors that I use for feeders, so underneath it's always hook the red wire to the red wire, and the white wire to the white wire, avoiding crossed feeds and shorts.

 DO have a seperate bus for DCC accessories, that why when track power is shorted to a section, there's still power to operate the accessories. Also run a non-DCC accessory bus to power other things.

 Document, document, document. Leave no DCC accessory decoder at the default address or ID, ALWAYS use a non-default address and keep a record of it.

                    --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by gregc on Tuesday, January 06, 2015 6:23 PM

The Pacific Southern Railway club minimizes wiring by using C/MRI using custom software on a central PC.  DCC is used to control locomotives using NCE cab bus.   (on a typical night, there might be 8 engineers running trains keeping 4 tower operators busy managing routes and signals).

C/MRI uses a serial bus to communicate with individually addressable control units throughout the layout.   Each control unit provides access to one one more I/O units each providing 8 input and 8 output signals used to control turnouts, report turnout positions, report block occupancy, setting signals, ...

The RS-488 bus (balanced pair RS-232) is just 2 pairs of wires starting at the PC and running from control unit to control unit.  (this is similar to NCE's cab bus).

greg - Philadelphia & Reading / Reading

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Posted by subman on Tuesday, January 06, 2015 6:50 PM

You have in the added building what most of us can only dream about.Off topic but relating to the area. With such a large building I would have added a crews lounge with a library in it. Possibly splitting the 2 workshops and adding a couple of feet to the width of the building Also I would have added 4 windows across the back of the building, 1 in the model workshop, 1 in the workshop (wood shop) & 2 in the trainroom opposite the 2 in the front of the room. Just my thoughts.

Bob D As long as you surface as many times as you dive you`ll be alive to read these posts.
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Posted by rrinker on Tuesday, January 06, 2015 7:40 PM

 Seems huge, but here were basements abound, it's not crazy huge - it's about the same space I have to work in, less the laundry room. The 'trick' in basement land is to find a one story house with a full basement. Quick quiz, what has a larger basement, a 2100 sq ft 2 story house (around here, fairly average) or a 1500 sq ft ranch home? The OP's space - if it were using the entire basement less mechanicals, could be a home of less than 1000 sq ft living space - quite a modest place, actually.

 Now, if there were jobs, and internet connectivity - I'd marry my GF and go live on her property out in Western PA. with 4 acres I'd probbaly get into ride-on size trains, and I could put up something REALLY crazy, like a 40x100 pole building, for a layout room. Like the "If I had a Million" Linn Westcott wrote about in MR (and it's in the back of 101 Track Plans), with that sort of space, I'd definitely have a nice lounge space, and work area. The layout itself still could be ridiculously large, but still a fraction of the size of Ken McCorry's. Alas, there are no IT jobs that pay anything like I make now in that area, and internet access is of the dialup speed variety (even when it's not dial-up).

                    --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by gmpullman on Tuesday, January 06, 2015 11:11 PM

Onewolf
There will be approx 80 turnouts driven by Tortoises and controlled via fascia toggles and/or DCC/computer control.

I'm very happy with the 50 or so Tortoises I have on my layout. I've yet to replace a single one and some of them are going on 20 years!

I kept (and still have) a thick, spiral bound notebook with ruled sheets on one side and 1/8" grid on the other. I made tabs for layout room, bench work, track, electrical, scenery and miscellaneous (maybe one or two more, I forget) but you get the idea. Like Randy says "write everything down" I had a few pages of each section just for ideas that popped into mind. As you build it is amazing how much you can forget.

Plan on a method of powering your turnout frogs. Better to have it done as you lay the turnouts (you can solder the wire to the frog much easier at the bench) the Tortoise has two SPDT switches or in some congested areas you can use a Tam Valley frog juicer. I pre-wired all 8 solder points on my Tortoises (plugs weren't that common then and with the pigtails already wired there's no need) I just coiled up the unused wires and tied them off with a little tie-wrap. Now that I'm adding signals and powering more of my frogs, the pigtails are there ready to use.

I suggest a stiffer throw wire rather than the stock wire that comes with the Tortoise. They come with .025" and I use .039"

Make every turnout bulletproof and don't get tempted to start scenery until all your trackwork and wiring are 100% ironclad...
It's easy to get distracted and say, I'll get back to that later.

Oh, and one more thing that others have preached here but I'm going to reinforce:

Install PLENTY of feeders! As your trackwork gets use and age all the little places where resistance can creep in—WILL! And a large percentage of DCC faults can be traced to poor track conductivity. 90% of all my joiners are soldered but there are still places that I'm finding voltage drop and I need to add feeders to track that has already been painted and ballasted.

I recently got a RR Amp Meter and with a ballast lamp attached to it I go around and find areas that need to be beefed up, electrically.

Hopefully, others will continue to post ideas here. These are just a few things that came to mind to add to the above suggestions.

Enjoy your planning! Ed

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Posted by Onewolf on Wednesday, January 07, 2015 10:27 AM

subman

You have in the added building what most of us can only dream about.Off topic but relating to the area. With such a large building I would have added a crews lounge with a library in it. Possibly splitting the 2 workshops and adding a couple of feet to the width of the building Also I would have added 4 windows across the back of the building, 1 in the model workshop, 1 in the workshop (wood shop) & 2 in the trainroom opposite the 2 in the front of the room. Just my thoughts.

 

 
The layout will have two levels on shelves that go all the way around the room so windows in the train room "get in the way". I have the two windows on the front of the trian room purely for architectural aesthetic reasons and they will be insulated and blocked off from the inside. I chose to not have windows in the model workshop and woodshop for a number of reasons: they take away from very valuable wall space, they introduce security access points, and they cost money to build.  The 'model workshop' will contain my library, computer, DCC programming station, and model construction/maintenance stations.  My building design was originally 7 1/2 feet wider but my wife requested that I narrow it because it's wider than our house. 

Modeling an HO gauge freelance version of the Union Pacific Oregon Short Line and the Utah Railway around 1957 in a world where Pirates from the Great Salt Lake founded Ogden, UT.

- Photo album of layout construction -

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Posted by Onewolf on Wednesday, January 07, 2015 10:30 AM

rrinker

 Seems huge, but here were basements abound, it's not crazy huge - it's about the same space I have to work in, less the laundry room. The 'trick' in basement land is to find a one story house with a full basement. Quick quiz, what has a larger basement, a 2100 sq ft 2 story house (around here, fairly average) or a 1500 sq ft ranch home? The OP's space - if it were using the entire basement less mechanicals, could be a home of less than 1000 sq ft living space - quite a modest place, actually.

 ...snip...

                    --Randy

Many people are surpised/shocked? at the size of my 'train room' but I explain that if we lived up in the "Great White North" I would have a much larger basement area to work with.  :)

I have spent 5-6 years designing a layout that meets my requirements and then I designed a building to fit the layout. 

Modeling an HO gauge freelance version of the Union Pacific Oregon Short Line and the Utah Railway around 1957 in a world where Pirates from the Great Salt Lake founded Ogden, UT.

- Photo album of layout construction -

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Posted by Onewolf on Wednesday, January 07, 2015 10:32 AM

Once again, thanks for all the great replies with loads of useful information.  It is much appreciated.

It's also great to be out of the post moderation penalty box!  :)

Modeling an HO gauge freelance version of the Union Pacific Oregon Short Line and the Utah Railway around 1957 in a world where Pirates from the Great Salt Lake founded Ogden, UT.

- Photo album of layout construction -

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Posted by trainPhD on Saturday, July 07, 2018 10:58 AM

Given the choice between solid wire or stranded wire, the best answer, from  electrical engineering, is stranded. Electricity travels on the outside of conductors (think Faraday cage), which means the larger the total surface area, the smaller the voltage drop. Stranded wire has more surface area than solid for a given gauge. 

The comment that solid wire is easier to solder is false. If you use flux on the joint before soldering, the solder will automaticlly wick into the strands. If it doesn't then you are not heating the joint enough, resulting in a cold solder joint.

Finally, stranded wire is much easier to pull through the layout

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Posted by riogrande5761 on Monday, July 09, 2018 1:24 PM

trainPhD,

onewolf is very far along on his layout now and his own PhD dissertation is well along!

http://cs.trains.com/mrr/f/11/t/244850.aspx?page=11

He may very will be able to accept grad students of his own soon.

Rio Grande.  The Action Road

Silly Aspie's, I have NT syndrome

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Posted by rrinker on Monday, July 09, 2018 1:28 PM

 Skin effective is not a factor at all with DC and barely (pretty much ignorable) evident at DCC frequencies. Now if we were dealing with sever a hundred MHz frequency... DCC is low kilohertz.

 However, the reason I use stranded is precisely because it is MUCH easier to pull through the benchwork. There really is no electrical/electronic reason for one over the other for model railroad purposes - I just pick the one that is easier to work with. I use solid for feeders, easily wrap around the strnaded bus and I don't bother with extra flux other than what's in the solder and have no issues with the solder penetrating the stands.

                                  --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

PED
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Posted by PED on Monday, July 09, 2018 7:25 PM

Onewolf

 The layout will have two levels on shelves that go all the way around the room so windows in the train room "get in the way". I have the two windows on the front of the trian room purely for architectural aesthetic reasons and they will be insulated and blocked off from the inside. 

 

If one of those windows has a problem (leaks, broken glass, etc), can you do all the repairs from the outside? If not, better make provisions for clearing a path to the inside for any repairs.

Also, need to plan for how your window cover up will appear from the outside. I did something similar then realized that the back side of my framework was easily visible from the outside. Looks tacky. I plan to cover the glass on the outside with some type of obscure film.

Paul

Washita and Santa Fe Railroad
Circa 1970's in south central Oklahoma

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