Model Train Layout Standard Wiring

Nowadays there is an option to wire your HO or N scale model train layout for standard DC or DCC (digital command control) or some sort of combo deal. Our focus for now is Standard DC wiring from a beginner to novice level.  By the way these concepts holds true for all scales AC or DC.  Standard DC is how everyone starts out running trains. You need a transformer or powerpak that provides the proper power for your model train scale, wired directly to the track.  The transformer has a knob or lever that you move to increase train speed (its really increasing the voltage to the track). This is the traditional way to run trains, and is a great part of the foundation of the hobby.  

Model Train Layout Transformer

If you are mounting your track permanently to a piece of wood (loop around the xmas tree) or any model train layout (as in its not in pieces directly on the rug) you really should be soldering all the rail joints. With that in mind if you have a simple 4'x8' type layout then you need at least 2 locations where you need to connect the transformer to each loop of track. Lets say one on the near side and one on the far side.  This will help keep the voltage constant all the way around and help with either dirty or cheap locomotives and/or dirty track.  Dirty = less conductive. 

If you have a larger layout then a 4'x8', then I would drop leads down every 6'-8' of track. Run "bus" or "common" power wires all the way around below each loop of track and connect the power "feeders" or "drops" to your common wires.  You do need to pay attention to the gage wire you are using. For HO & N scale 18 gauge is a minimum for the common wires 24 gauge for the drops. If you have multiple main lines then you need a new set of common wires for each so that you can have separate control of each line.  Please don't confuse power drops between main lines...wow that can be time consuming to figure out later. Its not a bad idea to use color codeing or wire markers or tags on your wires to help identify them. When you are crawling around under your model train layout in the dark some time in the future trying to fix something they come in handy.
That will cover you if you are simply running a few independent loops on a simple layout. If your loops have interconnecting switch tracks you need to make sure you put isolating (non conductive) rail joiners between the switch tracks so the independent lines don't short together. Also the same goes if you want to control a turn out independently from the main line. You need to add Insulated rail joiners at the exact point where you want that separate control to start. You may want to store a locomotive on that turn out and simply shut the power off to just that section using a toggle switch. Once the turnout is isolated from the main line you can wire it in the same fashion as described above but don't connect it directly to the main line common wires. Wire it back to the transformer independently and before attaching it install a toggle switch in line to one of the wires. Toggle on it connects that turn out to power. Toggle off no power to that turn out.



model train layout control panel

If you have a mess of turn outs and toggles then you need to build yourself a control panel so you can neatly display the switches and keep the wiring straight. This can be rather simple or complex as you see in the pic to the right.  A control panel brings things to another level and building one is a real art and far beyond the scope of this article.



terminal block



For larger layouts Some will say for every power drop you should use a terminal block. I prefer to just skin back the common wires (not cut them) and solder the power drops right in. Soldering takes any connector failure off the table years down the road.  You can then use some electrical tape around the solder joint and staple them up tight. Introducing some terminal blocks here an there is not a bad idea for future trouble shooting since with a turn of a screw you can isolate a section from the rest and just search out the problem there, but don't go crazy. 

The great thing about Standard DC wiring is how much it teaches someone fresh to the hobby about electronics and working with different tools. What we discussed here will be enough to get a beginning to novice model train layout up and running. As you add more turn outs or sidings, or yards, or loops you take the basic info laid out in this article and apply it. If you want sections of the main line to be turned on and off well use the concepts outlined for turn out toggle switches. More interconnecting loops, don't forget your isolating rail joiners.

Till next time have fun running some trains!