Section Three: Electrical

As you know, with Lionel and other three-rail electric trains using a center rail, the electric current is carried through the center rail, and the ground (or common in AC systems) is carried through the outside rails. This is fine for a normal, rather small layout, especially if the track and all equipment are in good operating condition. However, to provide for the best operating characteristics on our modules, we'll cover the basic wiring system in this section, leaving special wiring for accessories, traffic control, and more advanced uses for a later section.

Big Wire Bus Wire

For the most efficient electrical transmission, especially when modules are used together, there should be a bus wire from one end of each module to the other end. This bus wire (bus line or bus) will be made up of four wires according to our standards, no smaller in size than 16-gauge. However, we strongly recommend using 14-gauge wire, which is a little larger. (In the wire nomenclature, the smaller the number, the larger the wire.)

This wire should be of the stranded type, made up of many small wires covered with insulation. You might choose solid wire also covered with insulation, but we prefer the stranded, as we think it is better to work with, is more flexible, and is easier to thread through your module. These four wires making up the bus are for front mainline power, second mainline power, common (ground), and fixed voltage for turnouts, and possibly for some accessories.

Color-Coded Wire

We strongly recommend using wire with colored insulation as follows: white for the front mainline; red for the second mainline; black for common; and orange for fixed voltage. These colors are usually available in electronic or electrical supply stores and some of the larger auto parts stores. Unfortunately, our experience to this day shows that you can't find all of them at Radio Shack.

However, if you must use a single color for all four wires, extra care should be taken in wiring your modules so that they don't get mixed up, or you'll be in a mess. When you get these same-color wires onto the terminals and soldered onto the sockets and plugs, it's advisable to tag them at all such places with the name of the wire and a large dot at the appropriate color (white, red, black, orange).

The reason for this color coding is two-fold. First, for your own assistance in keeping wiring in order during the wiring process and to identify it at all times later on if, by some wild chance, some malfunction occurs. This holds true on your home layout, too, if you are building one. Second, to assist all other Tinplate Trackers who may have their modules in the same setup with yours, and for the same reason; to aid in knowing which wire is which and to help trace a malfunction should one occur.

The Terminal Barrier Strip

We've found that one way to do the wiring and keep ir orderly is to use terminal barrier blocks. They come with different numbers of terminals and in various sizes. They make for easy wiring hookups and quick changes when you need to make alterations to your modules or home layout. The corresponding upper and lower terminals are connected to each other but insulated from the adjacent terminals. If you need to attach several of the same kind of wires, e.g., four white wires, you can run a short piece of bare wire between two or more lower terminals.

Install a 10- or 12-terminal barrier strip in the center of your module below the deck. This can be in the center of the inside of the rear fascia (and with 3/8" plywood fascia it will take an extra thickness of plywood for reinforcement). Or it can be attached to a joist nearest the center. We prefer the former.

Bus wires from each end of the module will end at this barrier strip. It would be helpful to connect pairs of the terminal with small bits of bare wire, which will give you four places to connect each color wire.

Wires of corresponding colors can then lead from the terminal to the tracks, to which they should be soldered. One power connection and one common connection to each track should be sufficient in a 48" module. This will give you a power and common connection every four feet of track in a series of interconnected modules. Longer modules should have additional connections for both power and common.

Frequent connections of the common wire are just as important as the power wire for good electrical operation. As you know, AC current runs through both wires in both directions. The common terminals also can be used for your sidings and accessories, and the fixed voltage terminals can be used for your remote control turnouts, lights in manual turnouts, track bumpers on sidings, or signal lights.

Carrying the Current

With changes in motive power requirements, multiple transformers are frequently used, with the layout being divided into sections called blocks of a few to several modules, depending on the overall size of the setup. However, the electricity must still get from the transformer to the modules within the block. We've found that a simple and quick method is to install 4-pin female sockets at each end of each module and to electrically connect each module to its neighbors in the block by using jumper cables about 18" long (see Figure 3-4).

These sockets and plugs, sometimes called "Jones" sockets/plugs, are made by several companies. One brand is TRW-Cinch. Their 4-pin fascia-mounted socket is numbered S304AB and the plug with cable clamp is P304CCT. Radio Shack carries an identical part. Their number is 274-206 for the fascia-mount socket and 274-204 for the plugs. In a metropolitan area you may be able to find these items at a specialized surplus outlet and save quite a bit. (Editor's Note: Radio Shack has since stopped carrying these connectors. I've left the Radio Shack information in this document for reference purposes.)

Where do you install the sockets? There are several possible places. The original one was at each end of the rear fascia as shown in Figure 3-3. This works very well and is easy to use without hunting underneath for the sockets, and since they're flush-mounted, they are less prone to damage in transport. A second location, under the modules and 5" behind the front fascia instead of the rear fascia was suggested by Bob Griffin (see Figure 3-4). This has the advantage of hiding the jumper cables from public view and having them out of the way of the operating area. It also means that all jumper cables can be the same length regardless of the module sizes, such as 24"x48", 30"x48", etc. A third location is to have the sockets on pigtails, such as used by Matt Jackson and others, which we'll discuss later on.

These sockets, whatever their location, are required because they are the standardized way to move the current from one module to the next through the bus wires as opposed to the tracks themselves. Using the tracks is much less efficient electrically, likely to cause poor operation over long blocks, plus providing no means of transporting the fixed voltage through the modules.

Transformer Issues

When this manual was first written, there was only one practical choice for layout power -- the Lionel ZW. In recent years, there have been other power supplies from Right Of Way, MRC, MTH, and Lionel. The advent of more sophisticated sound and control systems for locomotives has raised compatibility issues with some transformers. This should be kept in mind if you are purshasing a transformer for use within a modular layout system.

Wiring by the Numbers

It is, of course, of the greatest importance that the proper wire be soldered to the proper contact point. Fortunately, these points are usually numbered on both parts -- the sockets and the plugs. Connect the white wire (first mainline) to No. 1; the red wire (second mainline) to No. 2; the black wire (common) to No. 3; and the orange wire (fixed voltage) to No. 4.

Warning! Some sockets and plugs are not numbered (or may be numbered differently), so if you find this to be the case, wire by position instead of by number. Note particularly the fronts and backs of these in the illustration. The positions of the numerals are reversed because when the plug is inserted into the socket, the effect is as if you folded the paper between the fronts of the socket and plug so the pins are placed over the corresponding holes.

Because the plugs and sockets are keyed, they will only go together in one position, which means everyone's wiring is going to match when we hook up the modules. The wires from these sockets run to the insulated barrier strip in the center of the module.

If we're using these sockets to carry power from one module to the next via the jumper cables, we need a way to connect to the transformer. Add a second socket at the eithert end of the module and connect it to the first one . If you have difficulty connecting the two sockets, just wire the second one directly to the barrier strip, the same as the first.

This is simpler and works just as well, but it does take a little more wire. You can attach two wires to a single terminal on the barrier strip.

This additional socket is not a requirement, but is strongly recommended. The reason is that if all modules have this socket, additional transformers can be added as power requirements dictate. It also becomes more convenient should your module be closest to the electrical wall outlets.

Jumper Cables

We've mentioned that we electrically connect the modules by using jumper cables. These are merely extensions of the main bus lines. They should be about 18" long, with the four wires (white, red, black, orange) connected to the TRW-Cinch P304CCT or Radio Shack 274-204 plugs at each end. The respective ends are plugged into adjoining modules, thus forming a single bus around the layout. You must have at least one jumper cable for each module. We suggest, however, that you carry an extra jumper cable or two in case someone forgets his or there is a problem with someone's cable.

This is the best way to ensure that plenty of current, including the common and the fixed voltage, reaches all modules. If one member fails to provide the bus wires and the jumper cables, it hampers operation for the whole group.

The Pigtail Story

Now that we've gotten you squared away on the wiring, and we hope carefully explained and pictured how to do it, we want to propose an alternate method alluded to earlier. It's called the pigtail method.

You omit the fascia-mounted sockets. You also omit one jumper cable. Instead, you create two "half" jumper cables -- one with a plug and cable clamp (TRW-Cinch P304CCT/Radio Shack 274-204); the other with a socket and cable clamp (TRW-Cinch S304CCT/Radio Shack 274-205). Notice the similarity of numbers. The sockets used here are different than those used in the fascias because they are meant to go on a cable rather than being flush mounted.

At the other ends of both pigtails, install spade or ring solderless terminals (ring are better because they can't accidentally pull off the terminal strip) and connect them to the corresponding terminals of the barrier blocks.

Important: Be sure that the pigtail with the plug goes on the left end of your module (from the operator's side) and the pigtail with the socket goes on the right. This will ensure that the pigtail on the left will connect with the module on the left regardless of whether it has conventional sockets or is using the pigtail system. The right module will need a jumper cable unless it is equipped with a pigtail as well. So, in any case, you should make a pair of jumper cables just to be safe. Modules of both types are in regular use. (Editor's note: On my modules, I used a modified pigtail with both plugs and sockets on the extreme ends of my pair of modules. This eliminated the need for jumpers for my modules, although I also had a set just in case someone needed an extra.)

To get power and common from the bus to the track, drop wires down from the track (soldered, of course) to each of the bus wires. From your front track a white wire would drop down to the bus in the center of the module; from the second track, a red wire would drop down; and from both tracks, a black wire (common) would drop down. You can remove a little insulation from your buses at this point and solder bare ends of your drop-wires to these places. Wrap the joints with electrical tape. Or, you can use solderless tap-in connectors (Radio Shack 64-3052 for 14-18 gauge wire). They'll be handy to use in several situations you will come up against in wiring modules as well as home layouts.

Pigtails are subject to damage if they hang loose during transport and set up. Devise a method to clamp the pigtails into the module while in transit so they don't hang loose and you shouldn't have a problem. You can use an ordinary clip such as often found to hold a broom handle in a closet or a tool of some kind in a shop.

Supplementary Power

Most accessories should operate of a supplementary power source because the primary (central) transformer will likely be overtaxed if a number of modules with many accessories are all pulling power from it. You should be able to use your own transformer for accessories, and a wire or wires should go from it to a separate terminal barrier strip to which all of your accessories can be attached. Using terminal barrier strips is a flexible way to wire. It aids in tracing wiring in case of trouble or to make alterations, and it's easy to add more, or remove, tracks and accessories without changing the basic wiring.

If you are using a supplementary transformer, all wiring from it to you accessories should be entirely separate from the bus wires and track wiring. If there is any connection between these two transformers and their wires, then the supplementary transformer must be in phase with the primary transformer. This is something that can be very simple to do or can become quite complicated, so we will not go into it at this point.

If you are adding your own power, or may want to later on, there is one more socket you can add. To attach your own transformer as supplementary power to operate your accessories or to power switching tracks for an industrial are, this extra socket is a must.

We've found that a 2-pin TRW-Cinch fascia-mounted socket, S302AB, works well here. Radio Shack carries a similar socket (274-201) and plug (274-203). This allows you to make two connections, such as one power and one common where your accessories or special track are completely separate from all of the main bus wiring.

As said above, if there is any connection between the supplementary transformer's wiring and the central transformer via track, common, or fixed voltage, then the transformers must be phased.

Make a Connection

It's time to test your wiring, and the best way is to use a test set -- two wires and a bulb, which you can make or purchase. Better still, you can put something on the track. Since your module is only 48" long, it might be better to use an illuminated car or track bumper rather than a prized locomotive. Besides, there will be plenty of time for that sort of thing after you build more modules and join them together.

Just plug your transformer into the second socket from the left (and into the wall outlet) and you're ready to go. By the way, did you think to make a connecting cable for your transformer? It's easy. Just take a piece of each of the four colored wires about 24" long and solder one end to another 4-pin plug with which you are now so familiar (but check your wiring) and put ring or spade terminals on the other ends. Be sure these are large enough to go over your transformer terminals. Terminals are highly preferred over just stripping the wire since they stay put and you don't have to worry about stray strands of wire shorting something out.

If you're using a ZW transformer, or any one that will operate two trains, your white wire goes to one variable throttle, red to another, and black to one of the common terminals (usually designated "U"). That leaves another terminal for the orange fixed voltage line, which should be adjusted to about 16 volts in normal operation.

Now by operating each throttle in turn, your bulb (or whatever you're testing with) will light up on the outside track with the white throttle; on the inside track with the red throttle. It doesn't?!? Then check all connections to see that you made them; that they are tight; that two bare wires aren't touching. That should do the trick. To check the fixed voltage line, connect your little test light to the orange and black posts of your insulated terminal block.


We hope the drawings and photos, along with the text, have made all this understandable, and will establish standards for all to follow. We're assuming, of course, that you've been running trains, but we wanted to spell out a few things in case you're not too familiar with wiring and electricity as it pertains to three-rail trains. It's not complicated; it may just sound that way.

Our Tinplate Tracker requirements -- the "must do's" -- are few and far between. The bus system and means of connecting modules are two of these. When one participant doesn't include a bus line, for example, it interrupts a strong flow of electricity around a modular layout and often causes a train to slow or even stall. Or, someone has turnouts or crossing gates on his module, but because the non-bus fellow is between him and the power source, these won't work. Please don't be that guy! Play fair with your fellow modelers. Now find some friends with modules and plug in with them and have some train fun!

  • Introduction
  • Simple Standards
  • What's in This Manual?
  • Section One: Module Construction
  • Section Two: Track
  • Section Four: Decoration and Scenery
  • Section Five: Special Modules

  • Back to Cover Page