Wiring – Best Practices for Model Railroads

Since no two model railroads are exactly the same, no two model railroads will be wired exactly the same. There are however standards that should ensure that all model railroads are wired the same way.

How Much Power Do I Need?

Lionel makes an assortment of power supplies and control systems, and additional power supply options are available from other sources as well. The amount of power you’ll need depends entirely upon the amount of power you’ll use. To begin, separate the power you’ll want for trains from the power you’ll want for everything else – lights, switch machines, animated accessories, etc. You can get a better overview of available power supplies here.


Lionel offers several power supplies to meet the demands of your layout. Proper wiring will ensure you get the most out of whichever supply you use.

If you will be using conventional control, you’ll want a variable voltage of up to 18 volts for your trains. With command control, a fixed 18 volts is required. The amperage needed will depend on the number and types of trains you plan to run. Obviously more trains = more power requirements. Lighted cars and older AC motors also draw increased power.

For all of your accessories, 14 volts of fixed AC is recommended. Likewise, the amperage requirements will depend on the number of lights, switches, accessories, etc.

You’ve probably started your empire with a starter set and a transformer like our CW-80. This power supply is great for your beginning, but you’ll find it is less and less adequate as you begin to add multiple accessories. Just like you can buy and add more track to expand your railroad, so too can you add multiple power supplies to meet the growing demand. Simply make sure the power supplies are in phase and you can tie multiple supplies together to boost your amperage. Not sure what “phasing transformers” means? Check this out.


The two wires you attached to your track with your starter set work well for a 40 x 60″ oval – but as your runs get longer voltage drop over the distance and joints can cause poor performance as your train gets further from the power source. The solution to this is a simple wiring bus. Not only will buses provided better power, on a large and complex layout, they can help keep the wiring neat and easy to maintain.

transformer buses

Color coded bus wires begin at the transformer and travel around the layout.

A bus wire is nothing more than a wire, or pair of wires, that carries power from the source around your layout. It can be tapped by feeder wires to connect it to the layout at any interval. These work for track, switches, accessories, etc. We highly recommend using different colors for each of your different mainline and accessory bus wires. This will make it much easier to trace a problem later.

Wire comes in many sizes in solid and stranded varieties. Stranded wire is really a bundle of smaller diameter wires wound together. Wire size is indicated by a number – the larger the number, the smaller the wire. Most house wiring in No. 12, solid wire. For your layout, we recommend a No. 16 stranded bus wire with No. 18 feeders. The feeders do not have to be as large because they are not as long and it is easier to attach the smaller wire to the tracks. Stranded wire offers better electrical flow (electricity flows around a wire, not through it) and it is easier to bend. We recommend adding feeders at least every 10 to 20 feet around the track.

For lights and other low amp accessories, even smaller wire can be used on the feeders. Lighted accessories should use No. 20 or 22 wire.Phone cable works very well for switch motors. It is color coded, easily available and cheap!


Track feeders connect the track to the bus.

You can use “common rail” or “common ground” wiring to further simplify things. As long as your transformers are in phase, you can run one common ground wire for all of your tracks. Then simply run an additional “hot AC” wire for the center rail of each separate loop.The bus wires for your tracks and accessories do not need to follow the track itself directly, but it is helpful if the bus wires and the things they supply are close. This minimizes the length of the feeders and reduces the “spider web” effect under the platform. It is a good idea to keep wires supported by running them through holes in platform supports or using some of the many different wire anchors available at a hardware store.

In addition to color coding, wire tags are also available to mark different elements under the layout. Maintaining a wiring diagram or planbook with notes that you update with your progress is also invaluable for future additions and maintenance. While this may not seem too important in the beginning when you only have a few tracks and accessories, as the railroad gets more complex, you’ll be glad you took the time to keep everything neat and consistent.

A few final tips:


Neatness counts! As your layout gets more complex, clear and consistent wiring becomes an important asset.

  • Use reliable crimp-on connectors and terminal strips at any connection where you may want to remove or change wiring later – for example, an accessory that may need to be removed from the platform for maintenance or storage.
  • Solder all permanent connections and protect with heat-shrink tubing or electrical tape.
  • Always check your wiring as you go. It is much easier to find a mistake before you’ve wired a dozen accessories!
  • An inexpensive electrical test meter is a great tool to keep on hand as you go. A simple light bulb can also be used to test many circuits – much easier and less risky than experimenting with a LEGACY locomotive!
  • Don’t be afraid of wiring. Taken one step at a time, wiring a layout is not very difficult and mistakes are easy to find and correct. Your Lionel transformers have built-in circuit breakers that will help prevent major catastrophes if you do make a mistake.
  • For a video review of this information, refer to our Wiring Best Practices Video. 

10 responses

22 06 2012

This is information that I ‘know’ but somehow seem to either forget or overlook when building my layout. A methodical approach really is best. Another excellent article.

10 05 2013
Michael Mellon

If a bus wire from multiple bricks are to supply multiple loops and share a common ground wire does the common from each brick need to join together
in a terminal block before one common ground wire goes out to the track.

13 05 2013
11 05 2013
Michael Mellon

If 16 gauge wire is good why not 14 gauge?
Is speaker wire as good as typical building construction wire?
Can the common ground wire from a transformer/controller at 14 volts
share the same common ground in a bus at a fixed 18 volts?
Will lionel’s Legacy signal broadcast as good on a layout wired using a terminal block with individual wires going to the track in a star pattern.
I am apprehensive about using paired wire that is jacketed for a bus if feeder
wires will be attached with suitcase connectors.

13 05 2013

You could use 14 gauge without any problem. For a larger layout, the extra capacity will be helpful. Speaker wire is not generally as robust as typical building wire. Yes, you can share a common ground. The star-pattern wiring plan is generally not a very efficient use of wire depending on the size / shape of your layout, but there is no reason it won’t work with LEGACY. I don’t recommend suitcase connectors for wiring. Although convenient, I have been told by several electricians that the connectors can allow moisture to become trapped inside causing corrosion.

24 05 2013
Joe Catalano

On a TMCC layout do I connect the Bus wire ends to the Transformer OR to the Powermaster?

27 07 2013
Jeremy Boyd

Thanks for the wiring tips, I am setting my new layout as we speak

13 10 2014
Egan Jones

On a 6 X 10 layout….how many busses should I need? Or will my 180 watt brick cover it all fine?

20 12 2014

how do you use a T.M.C.C. accessory motor controller ( 6-14183 ) to light all my buildings do I use the motor contacts also for this purpose. also can i use my trainmaster base for remote or mt legacy base.

29 12 2014
Dennis Stephens

How do I connect the feeder wire to the bus wire without cutting the bus wire?

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