Module Construction

Roadbed preparation:

The basic goal is, where the expansion track is, the roadbed or ballast must clear the expansion track; give yourself  at least 1mm of clearance. This minimizes bowing or humps/dips between modules. Even though it might not look as nice, if the expansion tracks are bowing up, you can tap them several times to get them level. With no space underneath, you cannot "tweak" the expansion tracks.

(read elsewhere on my methods of preparing the expansion tracks.)

Modules components / parts list:

  • Module wiring harnesses
  • cork roadbed - whose manufacture?
  • track - I will  use Micro-Trains flex - 990 40 901 - each piece is 12.5" long (10 in a package)
  • joiners - they come with the micro-trains track, but get some of their spares 990 40 909
  • expander track - Marklin 8592 - used to connect rails between modules, about $10 each
  • threaded inserts or wing nuts to hold modules together (threaded inserts better) 3/8 on the legs,  5/16 on the modules
  • tools - from Rodneys Railroad tools - straight track alignment, and the one that spaces double track and the one that spaces curved parallel tracks.
  • 1x3s
  • 1x4s
  • plywood ends
  • plywood half ends
  • 1/8"plywood tops for the Xs
  • 1/8" masonite for the finished sides 
  • rolls of rubberized cork roadbed material
  • 1/8" plywood for the tops of other modules
  • wood glue (Aleen's original tacky glue from Michaels is great for track)
  • 2" "yellow" drywall screws (why not the ordinary black?)
  • 4 x 8 sheets of plywood


After years of procrastination, I mentioned at a recent show that I did not have the time to build any but would like to find someone who would do it for a price. As luck would have it, I was talking to Don Fedjur. It did not take long to see he knew what he was doing, and doing it well. So I immediately contracted with him.

Just a few days later, 4 modules and Don appeared at my house. His construction method is clear pine, luan plywood and nicely countersunk torx head screws.

Don walked me through fitting the legs (he uses captive metal inserts in the frame and nice knobs to fix the feet, no wing nut for this guy!), and assembling the modules together. I started with two 3 foot modules and two 18 inch balloon modules.

Don also showed me how he cuts the self adhesive cork roadbed. He uses sheets of cork and cuts and bevels the roadbed himself. You can get pre-cut roadbed from Itty Bitty Lines

He gets a nice 45 degree bevel. He also showed me how to measure back, and then use a simple tool to draw the curves for the balloon modules.

He recommends painting the cork with paint, which keeps the cork from showing through when ballasting. I used one of those "fuzzy pad" brushes, and it made the paint go on easily and it was easy to do the beveled edge. I used Woodland Scenics Stone Gray C1218 on Don's recommendation. Painting the cork keeps it from showing through the ballast, since it's hardest to ballast the sides of the roadbed. It's water soluble too, makes easy cleanup.


Modules use a wiring system that allows you to "daisy chain" the electrical power to the standard tracks. There is some optional things I won't go into here.

Each "end" of a module has 2 connectors, one male and one female DB-25 connector. (These are the old computer RS-232 "serial" connectors).

The standard gives you the wiring setup, and which one is male, etc. A standard "through" module will have 4 connectors, since it has "two" ends. An "end" or "balloon" module only has 2 connectors, since it only has one "end".

To connect all the wires from these connectors,mounted the terminal strips facing down on the cross brace. Don drills 2 holes through the cross brace, and I threaded the wires through from one side to another to form a kind of strain relief.

Clips will hold the wires in place when transporting, and Don's suggestion to dress the cable off to the side allows a longer "reach" when necessary.

For the "balloon" modules, I was looking for something compact. I found a gender changer in my scrap box, and went "hmm":

Opening it up, it looked very promising, looks very easy to solder in wires, just run through the right holes:

But,these units are the same sex on each end, and I needed male to female. The solution was another gender changer, but very compact with no circuit board (called a slimline, about$5):

Here's pictures of the wiring to the gender changers, I bring the wires in from one side:

And solder to the other. Notice how the groups of 3 pins are bridged with solder? You can see pins 1-3, 4-6, 8-10, 11-13, 14-16 and 17-19 bridged. Looking carefully you can see the wires soldered to pins 1, 4, 8, 11, 14, anfd 17.


The combination works well.


Don also milled out and added captive metal threaded inserts for the NCE panel:

Here's a picture of the underneath of the modules with the power daisy-chained between the trwo 3 foot modules.

Here's a crummy picture of all 4 modules, ready to lay track.

Now it's time to assemble the track sections. I used Micro-Trains flex track. I trimmed the ends to slightly over 1 tie spacing with nippers, and then ground the ends square and flush. I use the side of a slow turning grinding wheel so I can see that the ends are square, you can use a fine dremel disc, whatever.

I pre-assembled the track sections so that the last tie came right to the 2-1/8" setback. Be careful, just holding the rails to add the joiners can bend the track. You can use Rodney's alignment tool to straighten out the track. Boy a bit different from G scale! We bolt it together and then lift it or stomp on it to get it level!

Time to lay track. Don came up with the idea to use a square tube as a straightedge. You can see it clamped down on the modules below:

The way I set the guide was to use a large caliper to read the width of the module. (24" one available at Harbor Freight for $10). Then divide in half and set caliper. Use this to mark centerline of the module.

Now, the track is exactly 1/2" wide at the ties, so the inner track guide should be set for 8-3/4".

Once the guide was set, we noticed that since the modules were not level (where are my adjustable feet Don ha ha) there was a gap between the cork and the guide in the middle. Adjust your legs to keep the guide tight against the cork.

Now all you have to do is apply the Aleens Original Tacky Glue to the roadbed, brush it out nicely in an even coat, and then drop your assembled track sections on it. Push the ties up against your guide, gently fix with T pins, sight down the rail for it being straight, and add some weight and leave it alone:

OK, a day to dry, and ready for the second set of track, the outer one. I used the Rodneys gauge to space parallel track. Put down the glue and ran the gauge back and forth several times to the the track in the right place. Then I laid some weights, moved the gauge a bit, added more weights and worked my way from one end to another:



A shelf and drawers for modules:

There were extra holes in my legs as delivered by Don. I was wondering what they were for something!

Here's a picture of what goes there:




Link to Z-bend yahoo group site files: 

Connecting modules:

what diamete/length? 1/4"
wing nuts? why not?
hole diameter?  3/8"
what is the location of the holes? 3" below the top of the cork roadbed, it should be modified to be measured from top of rail, since different rail heights are now a reality.

Module Legs

Is the standard 2x2?

Bolted from only one side (outside) or both sides with holes countersunk? (seems better) 

If you have classic 1/4" plywood then you need 49.5" long legs, if you don't use levelers You can cut 0.5" off later and add threaded levelers.

Otherwise, cut off a bunch of 48"ones and then cut a bunch of 1.5" blocks to stick up in the corners.  But that only leaves you with 2" before the bottom of the module (assuming 1x4 material which is 3.5" finished).  Not a lot of leverage for the leg to attach to but more than enough area to bolt on to. 

Jeff's legs are 47-15/16 (after cutting an 8' length in two) so he puts a 1" block above the leg to have it rest up against the top. 

(what's the best solution) 

Drill a 3/8" hole in the bottom (how deep?) and use a 1/4"-20 threaded insert from HD/Lowe's. There are 1/2" and 3/4" long inserts, use the longer ones, more stable. Jeff puts a c clamp (why not 2) on the leg end to avoid splitting while threading the insert. Find "elevator" bolts or flat heat bolts. (Is there a way to have a larger head to turn by hand? What about locking?

(maybe make a jig to hold the wood, and center the drill?) 

Jeff drills a 5/16" hole through the module and leg, then he countersinks the holes in the module for flathead 5/16" x 1.5" screw. Drill out the leg holes to 3/8" and thread in a 5/16" insert. (where to get?) 

Wiring to track:

I had some 24 gauge wire, which seems sufficient if I do the calculations, but the standard calls for 22. I bought 2 spools of 22 gauge solid core wire from our local Fry's electronics store. I measured the diameter of the wire, it is exactly 0.025". I got a #70 drill, which is 0.028" and drilled holes right next to each rail, on the outside. Strip the wire abut 1.5" and feed the wire up from beneath. Bend the wire over and form it so it nestles into the web of the rail. By twisting the spool underneath, you can make sure the wire is tight up against the rail. Add some paste flux and solder, keeping the iron on the wire, not the rail. Keep the solder pressed at the junction of the rail and the wire. As soon as the rail is hot enough solder will flow. Heating the rail first is a mistake.

I soldered one set of feeders at the middle of each track section on each module.

Other construction notes:

Glue for blue foam: Apparently there is one version of "Liquid Nails" that works, but another that eats the foam. Will try to get the exact name. LockTite GpoerGrab Foamboard adhesive is also good. In a white tube, but there are several versions, make sure it says "FOAMBOARD" on it, or it will eat the foam:

Don Fedjur reports that the above adhesives work well, but add significant weight to your module. He says that any liquid polyurethane adhesive such as Elmer'r or Gorilla Glue work well. Spray/mist some water on the surfaces, then apply the glue, which will foam as it reacts with the water. You should clamp it to ensure a good bond.

Where to buy:

Misc Notes on modules:

  • Threaded inserts beat wing nuts.
  • Knurled handled bolts beat carriage bolts for one-handed setup.
  • A set of braced 1x2s beats two wobbly 2x2 legs.
  • Harbor Freight, baby! The best place for tools.
  • The "home" module doesn't need adjustable legs if it is at the right height. All other modules must adjust to it. The home module should be in the middle of the layout.
  • End modules may not need legs.
  • Where modules meet, only one needs legs.
  • Tracks must be wiped hourly during operation.
  • Electrical leads should be soldered from the underside of the track. (I still haven't gotten my Z-scale electricians to do this right.)


Notes on what to bring to a show:

laser level with the crosshairs?

Nce cab

Cab cable

110v Extension cord


Track cleaner car

Magic goop

something to do internet

Laptop and power



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