• Stephen Strum

Building a 3.5' x 5.5' N Scale Layout Part 2: Track and Wiring

Updated: Apr 20

A lot has been completed on the layout and will be covered in this post (once I have all of it finished in a week or two):

  1. All track has been installed with the track plan revised slightly.

  2. All track wiring has been completed

  3. All turnouts are now wired and can be operated by push buttons on the front of the layout (or from the DCC throttle).

  4. Power for layout lighting has been installed along with control switches (for future structures, street lights, etc.

  5. The Digitrax DCC system is ready to go.

  6. I painted the base layer of scenery before installing the track

  7. I installed bridge piers

  8. New metal legs have been installed that are a little taller, far more sturdy, and easy to take off and put back on (important since this layout has to travel).

  9. Two coats of cherry stain and three coats of satin polyurethane have been applied to the wood frame of the layout.

  10. A single power cord for the layout has been installed.

Here is what the layout now looks like. I think it looks pretty sharp. Track weathering, ballast, and the remainder of the base scenery will come next, followed by structure building and installation.

I did have to revise the track plan slightly. I installed short 1.14" straight track sections to the left of the bridges on the front part of the layout. This was to allow for better clearance when entering the bridge when trains are coming around the layout counter-clockwise. That, in turn, required adjusting the track to the right of the bridges. I also slightly adjusted some track pieces on other portions of the layout so things would fit a little better or track sections would line up where I wanted to install power leads and that kind of thing. Here is the revised track plan and track part list. I've also marked where I installed insulated rail joiners as well as power leads to the layout.


Kato Unitrack Track List

20000: Straight 9.76". 8

20001: Straight 9.76". (double plate track) 1

20010: Straight 7.32". 2

20020: Straight 4.88". 4

20040: Straight 2.44". 6

20048: Buffer/Bumper Type C, 1.99". 4

20070: Straight 1.79". 5

20071: Straight 1.14". 14

20120: Curve radius 12.4", angle 45º 5

20121: Curve radius 12.4", angle 15º 2

20130: Curve radius 13.7", angle 30º 9

20132: Curve radius 13.7", angle 45º 1

20140: Curve radius 15", angle 30º 3

20150: Curve radius 28.27", angle 15º 1

20160: Curve radius 18.94", angle 15º 7

20181: Curve radius 15"+16.3", angle 45º (concrete) (superelevated) 2

20182L: Curved transition radius 15"+16.3", angle 22.5º (left) (concrete) 1

20182: Curved transition radius 15"+16.3", angle 22.5º (right) (concrete) 1

20185: Curve radius 17.6"+18.9", angle 45º (concrete) (superelevated) 2

20186L: Curved transition radius 17.6"+18.9", angle 22.5º (left) (concrete) 1

20186R: Curved transition radius 17.6"+18.9", angle 22.5º (right) (concrete) 1

20202: Left turnout 7.32". (remote) 1

20203: Right turnout 7.32". (remote) 3

20210: Double crossover 12.2". 15º 1

20231: Right crossover 9.76". 1

20452: Straight 7.32". (bridge) (gray) 1

20457: Straight 7.32". (bridge) (gray) 2

20541: Curve radius 15"+16.3", angle 45º (viaduct) 2


Anyway, here is what I did since the last post to get the layout to the current point of completion. Before installing the track and the wiring, I went around the layout and sanded the foam smooth so there were no small bumps that would prevent the track from laying flat. Once that was done and cleaned up I put the track back on the layout and marked out where I wanted the power leads to go.

This layout is being wired for DCC operation and I'm using a Digitrax Zephyr DCC system to power and control things. This base station is great for smaller layouts and has a built-in throttle plus allows other throttles to be connected. I have also connected a Digitrax panel I installed into the front of the layout fascia to the base station, allowing you to plug in handheld throttles. Since the base station is small and lightweight, I have it mounted to the layout with velcro. I have two strips of Velcro attached to the front of a wood panel that I attached to the layout frame with a piano hinge. A couple of wood blocks on the sides keep the panel from hanging flat. The base station and a handheld throttle or two can then be attached to the velcro strips, but still be removed easily if needed. When moving the layout I can take off the Digitrax base station, fold up the panel that holds them, and then fit the layout in the back of my vehicle for transport.


You can see here the locations I decided to add power leads using Kato terminal rail joiners (in red), as well as where I put insulated rail joiners (in black). The Kato #6 turnouts are power routing, and so to help prevent shorts, I put insulated joiners on the frog end of the turnouts and made sure I had power coming in by the point side of the turnout. Even so, if you run a train into the turnout from the frog side, and the turnout is not aligned to the track the train is on, a short will occur once the train crosses the insulated joiners.


The crossovers are insulated already though, and so while they are DCC friendly, you do need to apply power to each leg of the cross-over as power will not flow from one side to the other. You don't have to have the power leads directly attached to the ends of the crossover, but make sure you have power connected to tracks on each side somewhere.


I tried to make sure there was power connected to each track in between sets of turnouts as well as in a couple of extra locations for redundancy.

Using a long drill bit, I drilled a hole through the thick layers of foam at all the locations where the power leads needed to go, as well as where the wires for the turnout motors were going to be located. I then ran the wires down through each hole. Since the holes were fairly large, this wasn't hard, though if you use smaller holes you can always put a drinking straw in the hole to make it easier to run the wires through since they can snag easily on the foam. Once the wires are through you can then pull the straw out.

The most important thing when connecting the terminal rail joiners or soldering on the wire leads if you do that is to keep things consistent. In this case, the terminal joiners have a blue and a white wire. I made sure the blue wire was always on the outside rail (closest to the layout edge) and the white wire on the inner rail. This way, I could connect all the blue wires together and all the white wires together without creating a short circuit.


The Kato single cross-over was set up to be power routing. I wasn't sure if this would cause a problem or not, so I moved the screws to the non-power routing locations.

Once the wires were all in place, I used a pair of wire strippers to cut off some of the excess wire and to strip all the ends.


I then ran a pair of heavier gauge wires from the Digitrax base station to the underside of the layout to serve as the bus wires. I connected all the blue power lead wires from the track to the blue bus wire and all the white wires to the green wire. Then, I had a locomotive running on the layout while I connected each group of wires under the layout to the blue and green bus wires. If I heard the locomotive stop I knew that I had created a short (if the spark when touching the wires didn't make it obvious) but as long as the locomotive kept running then I could keep connecting wires.

Once everything was connected and there weren't any issues, I went back and soldered all the wire connections and then covered them with a couple of coatings of liquid electrical tape. When connecting the wires, I try to make sure they are always secure without the solder. I do that by wrapping the two wires around each other, then folding back the wire onto itself so they are securely attached. You want to have a strong physical connection first and not rely on the solder to hold the wires together. When soldering the wires, I like to keep the heat on one side and let the solder flow through from the other. I use a Hako soldering station that has an adjustable temperature, but generally, one that is hotter or higher wattage output will heat your connection faster. Once things have cooled a bit I come back with the liquid electrical tape. Often I'll use heat shrink tubing as well since that is probably more robust, but in places where there isn't much risk for wires shorting out or where the tubing is hard to use I just use the liquid tape. It can be messy, however, so you might want to wear gloves when using it.


At this point, I decided to get some bridge piers put in place since that would be hard to do once the track was glued down. I made the piers out of pieces of poplar, just cutting the wood to size and sanding it smooth. I glued the piers in place with wood glue and then mixed up some sculptamold and used that to help blend the piers into the scenery. Later I would come back and paint the piers gray as well as the surrounding scenery.


While testing the layout with different locomotives and rolling stock I learned that I needed to shift the two bridges on the front of the layout off to the right an inch or so in order to prevent longer pieces of rolling stock from hitting the ends of the bridge when coming in from the curved track side. So I added a couple of 1.14" pieces of track to the left of the bridge and then adjusted the track pieces to the right so things would still line up. The track plans shown previously include the extra 1.14" pieces of track.



Next, I moved on to drilling holes in the front of the layout for the push-button controls I'm using for the turnout controls. I marked the location I wanted each button and clamped a board to the layout frame to use as a guide. Then I used a 3/4" drill bit to drill each hole since the push buttons have a diameter of just slightly under 3/4". I put some wood putty around the inside of each hole as well as around the front edge so I would have a smooth opening once I sanded things down and wouldn't have any gaps around the edge of the buttons.




I soldered wires to the back of each button, then temporarily installed each button in the layout frame. I then hooked up wires to each of the two DS64 units I'm using to control the turnouts that will connect to the DCC bus line that powers the track. I attached these with some double-sided tape to the bottom of the layout for now, and later would permanently install them with some screws once I was ready to actually wire the turnouts


At this point, I moved on to soldering most of the rail joints. This isn't actually needed, and if your layout will see large temperature swings, soldering every joint will cause problems as the metal rails expand with hotter temperatures. If there is no room to expand you can get some kinks or buckles in the rail. I have left some of the rail joints unsoldered, and will cut some expansion gaps in the rails if needed as conditions warm. But, having a lot of the joints soldered does help with overall electrical conductivity around the layout, limiting the number of dead spots that might spring up over time. Alternatively, you could just use more terminal rail joiners or solder more power leads to the track.


When soldering rail joints, like with wires, I apply the heat to one side and the solder to the other to help ensure I'm getting a solid joint. If you apply the heat to the solder, it will melt and spread across the joint, but may not bond as well. Since the Unitrack is plastic, it may soften while you are soldering. So, be sure the rail joints are still aligned after the solder cools. If they are not, you can come back and heat the joint a bit and push the rails back into alignment.


Once the soldering is done, go back over each joint and file off any solder from the top or inside of the rail. This is also a good time to file the joints smooth in general to make sure there are no bumps that might derail a freight car.



At this point, I figured I should get some painting done before gluing down the track. I first painted the bridge piers, then applied a wash of brown paint under the bridges. Then I painted the same brown wash on the remainder of the layout, moving the track out of the way as I went along.


To glue down the track, I simply used my, Surebonder hot glue gun. The Kato track can be a little tricky to hot glue down since most of the roadbed is hollow, but there are some spots where glue can grab onto. You could simply spread some white glue under the track as well, but the hot glue helps hold things in place quickly. The track isn't firmly attached everywhere, but I'll be gluing ballast down along the sides of the track, and that will permanently anchor the track in place once I do that. I added some metal machinist blocks in places while I was gluing to keep things from shifting while gluing other sections of the track, but any kind of heavy object will work certainly.


Once the track was glued down I could flip the layout on its side in order to complete all the wiring. I tried to run most of the track wires through some plastic cable raceway to keep them neat and tidy. Doing so not only makes the underside of the layout look nicer, but it also makes it safer to transport the layout since there is less risk that some wires will snag on something and be ripped out.


I then moved on to wiring up the turnouts. Again, the turnouts were wired using two Digitrax DS64 units. You don't need to use these, but it does make control of them easier. You could just use the Kato switch levers, or your own momentary toggle switches or push buttons. But, the DS64 units allow you to control the turnouts both by push buttons and from your DCC throttle.


The DS64 units can control 4 turnouts each, so I needed two units to control the 6 turnouts and cross-overs on the layout.



Wiring is fairly straightforward, but you have to make sure you don't connect a wire to the wrong terminal. First, I connected all the wires from the push button turnout controls to a long terminal strip. Then I added another terminal strip to connect wires from the DCC bus to, and then from there to the DS64 units. This way if I need to remove one of the units I won't have to worry about any solder joints.


Then, it was a matter of connecting the two wires from each turnout motor to one of the 4 pairs of connection points on each DS64 unit. The connections on the DS64 are labeled for turnouts 1, 2, 3, and 4, so getting those connections made was easy with the built-in screw terminals.

To control the turnouts by momentary push button, you connect one wire from each push button to one of the switch control terminals with the S1 terminal controlling the turnout connected to the 1st set of terminals, S2 controlling the turnout to the 2nd set of terminals, etc. The other wires from each push button are connected together and then connected to the common terminal on the DS64 unit. So, it was just a matter of making sure I connected the wires from the DS64 to the correct switch wires at the terminal strip.



Once all the wires were connected, I again used some pieces of cable raceway to contain all the wires and make everything look a lot neater.

The way the units work with push buttons is that every push of the button will flip the direction of the turnout allowing one button to control both directions of the turnout. So, only 6 push buttons are needed to control the 6 turnouts. These pushbuttons are really nice and sit nearly flush to the layout fascia. I had original planned on recessing the buttons so they wouldn't be damaged in transit, but the flat nature of the buttons allows them to be mounted flush on the fascia.


While I don't have any lighting installed on the layout at this time, I went ahead and set up a 12v power supply, controls, and a couple of terminal strips to make it easy to connect lighting later in the layout build process. I have a regular light switch with three toggle switches on it that you might use in your home built into the layout fascia. Each of these buttons can turn on a set of lights or other accessories. The wires from the power supply and the switches are connected to the terminal strip and then I can connect wires from the terminal strip to groups of layout lighting later on. So, I might have one switch control structure lighting, one control street lights, and another control lighted signs or other accessories.


You can see the completed layout wiring here. Well, except for the future wiring that will be installed for structure and street lights. I have my DS64 units in the middle:

The terminal strip above that which oins the wires from the push buttons to those from the DS64 units:

The Digitrax panel for connecting hand-held throttle at the top that is in turn connected to the Zephyr base station with a single cable:

All the wires to the control switches for the layout lighting run through the fascia here:

And then to this terminal strip to which I can connect future lighting:

All the wires to the Digitrax Zephyr base station run up through the layout here:

Then I have the power from the base station as well as a 12V DC power supply connected to an extension cord mounted to the underside of the layout so only a single power cord is needed to power everything:


Another change I made to the layout this update was to install new legs on the corners of the layout.


I originally used some wood legs that screwed onto the layout base, as well as a set of bolt-on legs that were much sturdier. While those bigger legs looked nice, they were somewhat difficult to get on and off. The smaller legs that screwed on just weren't sturdy enough. So, I looked around and found this set of metal legs at the tablelegsonline.com website. This kit includes heavy-duty plates that you can screw to the bottom of your table or layout project, each attaching with 8 screws. The kit also includes plates that allow you to fold the legs in so you don't have to remove them. I tried those, but those put a lot of stress on the bottom of the layout when locking them in place, and so I was worried about long-term damage from use. Further, the folding mechanism, while quite sturdy, wasn't quite as sturdy as the heavy stationary metal plates that allow you to really thread the legs on tightly. These legs are a couple of inches in diameter and have adjustable plastic feet. This allows you to level the layout, and the plastic feet will also prevent the legs from scratching your floor surface.

At this point, I decided to finish the layout frame. I sanded everything down with a series, of course, medium, and then fine-grit sandpaper on my orbital sander to get a nice smooth surface and to sand off any glue or paint that was on the frame. Once that was done and the dust wiped off, I taped off the controls and then put two applications of cherry stain on the layout, wiping off any excess each time. After a day of drying time, I applied three coats of satin polyurethane. The poly coats give the wood a lot of protection, making it more resistant to damage, while also giving the wood a much richer look. You could use a semi-gloss or gloss finish as well if you want the wood to have a glossier look. I plan to cover the wood while doing scenery work, but if I do get any paint or glue on the frame, I should be able to clean that off now that the wood is sealed and coated with polyurethane.

I may need to lightly sand everything and apply another coat of polyurethane after the layout construction is complete. While I could have waited to do this after the layout construction was done, I would have needed to sand the wood down even more to make sure I had sanded out any glue or paint that had soaked into the wood, as those areas wouldn't take the stain as well and would have a different color to them and not look as good in the end. Also, I wanted to get all the controls installed, and it would be harder to go back and do the finishing once all the controls were installed.

Once the final coat of polyurethane had dried I installed the controls back on the layout. I simply glued in the pushbuttons with hot glue, while the switches for the layout lighting and the control panel for the throttle units were attached with screws.

To hold the control panel on I put some strips of velcro on the back of the Zephyr unit, then ran two horizontal strips of velcro on the wood panel it was to be mounted on. So the self-adhesive velcro wouldn't pull off over time, I attached each strip with three screws as well. Then I was able to just stick on the base station unit, and easily attach the handheld throttle as well.

So, the layout is looking pretty good at this point and trains are running reliably all around the layout. The wiring took a while to do, but now with that part of the work done, I'm ready to move onto scenery and structures, which is always the part of construction that is more fun.




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