Wiring for a model railroad layout can be easy or complicated. I like to manage my wiring so that later on, I’ll be able to trace each wire back to its source.
Years ago, I developed my own personal wiring color codes along with standardized schematics for repetitious situations that I keep in a notebook along with my other layout information. Wire gauge standardization is important, too, as a function of wire length and electrical current considerations. More length and/or more current require a heavier gauge wire.
Related video: Wiring a Model Railroad Track
On large layouts, I’ve used buss wire up to 12-gauge (stranded for easier installation) and down to 22-gauge solid wire track feeders that solder to the outside of the rail, hardly seen. That includes the code 55 rail that I use for my Sn3 trackage. And, I’m a fan of using labeled terminal strips at wire junctions to avoid the “What is this wire for?” problems.
Related video: Model Railroad Wiring Considerations
I like to string wiring neatly into bundles that are tie-wrapped and hung through or under the benchwork, avoiding access areas. Buss wires for track feeders should ideally be run under the primary trackage, enabling the use of short, light gauge feeder wires up to the rails.
In the old days, block wiring required a feed wire from a control panel to each block. In a large layout, that could add up to a lot of wire! Remember the old “spaghetti bowl” wiring scenarios? If you add switch control wiring, along with signal and accessory wiring, you could end up with a real mess! One of the great benefits of DCC is wiring simplification. I know, I’ve done it both ways!
My suggestion is to be as logical as possible when installing wiring so you don’t end up pulling your hair out later. If you have any specific wiring questions, leave us a comment below or feel free to email me directly at doug@modelrailroadacademy.com. I’d love to talk with you.
More in this series:
So You Want to Build a Model Railroad Layout?
Choosing Model Railroad Track Configurations
Assigning a Theme for Your Model Railroad Layout
Ideas for Unique Layout Concepts
Tips on Trackwork
Helpful Tips for Model Railroad Wiring
Creative Ideas for Model Railroad Structures
Is there a way to run wire throughout my O gauge layout so I can get better running speed throughout my layout. I’m getting voltage drop when it gets far away from the power of electricity. Any throughs, please help me. Would really like to get my Trains running smoothly.
Hello Benjamin,
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Sarah
Model Railroad Academy Video Membership
My layout is all Lionel tubular track. Could you provide me the pros & cons and the ROI of converting from tubular track to Lionel Fast Track. Tks.
Hello William,
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Thanks!
Nice site
I’m building a layout for a train show/display at my Scout booth. I want a button kids can push and make the trains run for a specific time. I’m trying to figure out an inexpensive way to do it. I can make it run as long as you hold the button, but I’m going to need some kind of circuit to get it to stay on. Got any ideas?
Thanks
IC Joe
Hi Joseph,
Thank you for contacting us.
Our expert suggested that you check around. Push buttons are also available in a push on-push off configuration.
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Sincerely,
Sarah
Model Railroad Academy Video Membership
I have visual challenges and am looking for some help on how to wire my ho scale track. It goes completely around the room so it’s probably 30 ft long. Can you tell me about wring bus bars or terminals and where to get them or how to make them myself. Thank you so much
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Building first DCC layout. A small 2×8’ shelf. Using starter DCC system from NCE. This may be a dumb question but here goes anyway. With such a small layout could I forego a buss line and just go from pcp panel to multiple terminal strips and then run feeder wires to the different tracks/sidings from the terminal strips.
Hello Cliff,
Thank you for contacting us. Great question! The ‘Ask an Expert’ section is currently for members of our online community. By becoming a member, you will have access to our expert’s knowledge in Model Railroading. With your membership you will also receive discounts on products and hours of Premium video content.
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Joan
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Question: when installing bus wires beneath your layout table does the bus wires need to golliw the shape of the main line track?
Hello Rick,
Thank you for contacting us. Great question! The ‘Ask an Expert’ section is currently for members of our online community. By becoming a member, you will have access to our expert’s knowledge in Model Railroading. With your membership you will also receive discounts on products and hours of Premium video content.
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Sincerely,
Joan
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Model Railroad Wiring is my primary interest, I am interested in any information in this area, no matter how seemingly arcane. What’s old hat to fellow railroad modellers, is sparkly new to me. I look forward to many informative articles on this site. Please keep it runnin’ folks!
Wiring points for DCC is one issue for me
I have no Experian in electrics
want to wire a DCC Ho layout that has six 4′ by 8′ base tables in a elongated U Shape layout.
I was planning on using 14 gauge AWG stranded wire. Is this good enough?
Hi David,
Thank you for your patience while I asked the expert, here is his reply:
Yes, that should be great. I would connect my power station to the buss near the center.
Kind Regards,
Douglas
Model Railroad Academy
Hi David
I have a board 4.5m x 1.8m I use 2.5mm ring main around the outside edge of the board I use springs to tension at one corner than connect the main by one wire same gauge to the control unit, all droppers are 7/0.02, as for the spring idea it keeps the main tight and I strip back a little insulation and solder all connections except for track only solder to each piece or if I have 2 smaller pieces of track I might solder them together then a dropper, I also use liquid tape on the joints.
Cheers
Ross
Hi Doug, I am working with O scale and will eventually use DCS as I have a couple of MTH 3.0 locomotives. Now for my question to you, my train table is 5×10, I have run a 14ga. solid set of wires (black and white) and have 18ga. for my feeders, since I am pretty much ignorant to train wiring, I would like to ask what do I do with the ends of my buss wires? do I just leave them at the end of the run and put wire nuts/electric tape on each? If it matters, I will be using a post war, 275 watt ZW transformer that has been refurbished. Thanks a lot for any help.
Hi Francis. Sure. You could just cap them off with wire nuts.
Thanks
Doug-Model Railroad Academy
how do you run bus lines without the use of suitcase connectors?
Hi John,
That’s a great question. You could certainly use terminal blocks at each feeder set. I like what’s called Euro-Terms. You can buy them bulk on line. The ability to disconnect sections of the buss wires is great for trouble shooting. And, I’ve seen the buss wires stripped for a short section and the feeders soldered. Let me know how you make out.
Hope this helps,
Douglas
Model Railroad Academy Video Membership
Hi John what I did is run buss wires around the outer edge of my board 4.5m x 1.8m, I used springs to tension at one corner, I just strip back a little insulation on the buss wire and connect a dropper and solder, it’s only 12v to 24v so touching it is not a problem and the springs always have tension so they never touch… but you could use liquid tape to seal the joint, I never use suite case joiners as it is a dry joint to start with and it will corrode and create a high resistant joint, as I said my board is 4.5m x 1.8m so any dropper and that is if one is going to the middle of the board can not be longer than .9m maximum but most are less than .3m, I solder every thing except the track fish plates, I have in the past and found it buckles the track, but in saying all this try things for yourself do it a couple of different ways and find a way for you.
Cheers
Ross
My dream to create miniature Ho scale model railroad world in Mumbai, India. I want technical and technology help regarding this model railroad.
I used 18 2o through out mine for the gauge. Each wire has its own point of contact and no more then 1 amp of power throughout them. I do not use buss wires and avoid suitcases this way they can become unreliable in time / I have seen this happen on cars so it is better to avoid unwanted issues. I have a max of 5 amps for 9 atlas 205,s at 4 connections each one. and 14 215,s and 5 amps through them at 6 connections each 215. I use the power when needed and each area has tested ok.
Consider changing your name to HO Model Railroading Academy, because you don’t have anything helpful or useful for O gauge.
I agree, never anything on O gauge!
Question: I am starting a dcc HO layout in my garage. It will be 3-4X6 sheets with 2 main line loops around the perimeter. do i need a main buss loop for both the inner loop & outer loop or rjust run feeders from both loops down to 1 main buss run?? I am planning on 14 Ga. for the Buss.
thanks.
Hello Bob,
I would do separate buss loops as you may want to separate them electrically with DCC circuit breakers. A 14 gauge buss is fine, but it might be heavier than you really need.
Hope this helps,
Douglas
Model Railroad Academy Video Membership
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I am retired and want to build a layout with my grandson… I have a 12×16 building but I am willing to take all the advice I can get…. I am completly ignorant and willing to learn
Take your time and test a few tracks and switches, The key to this all is to ensure the wireing is in sync with the next connection, ( north/South wire connections allowing the train to continue without any shortage . Once you have a few connections with wiring that run smoothly you will find this easier. Just do not place too many switches in until you have the base connections running smoothly. I know where you are coming from. good luck and enjoy and again take your time
I often see comment about using DCC. But I have yet to find information that I can get my 65 yr old brain around. Any suggestions.
Hello Billy,
I did a search for what we have on the site for DCC and here are the results. Scroll down past the Goggle Ads to find the results from the site. https://www.modelrailroadacademy.com/?s=dcc
Thanks,
Becky
Model Railroad Academy Video Membership
I am going to run 18 g feeders from my 14 g buss on my analog HO layout. Is it best to use solid or twisted for the feeders? Should the feeders be solid copper or can you use something else. If something else, what is good as I know there are many different types of copper coated wire. What gauge wire should be used for turnouts, can I use the same 18 g I’m using for the feeders, run on the turnouts is about 10 feet? Thanks in advance.
Hello Bob,
Here’s my view on this. I run my buss wires as close as possible directly under my main lines, then I use a #22 solid wire from the buss to the rail and solder it to the bottom or outside of the rail. The feeder becomes very inconspicuous that way.
For turnouts, if they are a DC motor type, I use #22 stranded wire as they se very little current. Ten feet is not a problem.
Hope this helps,
Douglas MRA Video Membership
Bus wire and feeders… Do I have to solder bus wire to rails or is it a loose wire all along layout and only feeders have to be soldered to rails ?
Hello Guy, the buss wire would be a heavy gauge wire that carries the layout power around under the layout. Light gauge (I use solid) feeder wires would run short distances from the buss wire to a solder connection on the bottom or outside of the rail. You can use crimp-type (suitcase) wire connectors for the feeder connection to the buss wires.
Bus Line is the wire running underneath the layout. The feeder lines are the wires that are branching from these wires. Example of this would be a tree. the right side of tree has a branch with many single feeder branches attached to it. These are feeder branches. The other side of the tree has the same branch with the same feeders off that same branch. So the branch on the left side is running positive sap and the branch on the right side is running negative sap. this is how you would wire your railroad. Solder the bottom of the rails every 6 to 10 feet with a red and black wire and attach them to the two different color bus wires that are running under the layout. After the track is completely wire then you attach these wire to the power supply and run your train.
Does anyone have information as to what power supply I may need for a HO layout starting as a 4’X8″ but will expand to 16′ long. A loop all the way around the perimeter to start and then expansion for maintenance yard and grain silo, a rail yard and a mine setup. Depending on how that plays out, more may be added. I am going to use flextrack. Switches will be involved as well.
>Hi, Christopher. You didn’t say weather you were doing DC or DCC. HO trains don’t take all that much current. As long as you install feeders periodically, a 5 amp supply would be plenty good.
I would say 5 amps is plenty. On our club layout we run DCC with PSX breakers set at default 3.81A, and routinely run long double stack trains (85 or more) and 6 to 10 SD90 locos all powered, with sound and lights. In fact any more than 5 amps for HO can be dangerous when a short occurs. This would apply to DC or DCC. If you are planning to go DCC in the future, or more importantly if you don’t think you will you should wire your layout for DCC. If it will run on DCC then DC is easy, and then it is a matter of just switching the power supply and adding decoders to the locos. For a small layout like you describe I would start with an NCE Power Cab, it will probably be all you need for a long time.