Building A Test Loop

Since the test loop project is a dry run for a couple of key methods I expect to use on the new layout, I decided to start with a little formal planning using CadRail from Sandia Software. Years ago I tried an earlier version of their product and found it difficult to use. This time I did much better. The current version, for all its CAD power, is really pretty easy to use for basic planning. I downloaded the demo, spent a few hours doing the tutorial, and was able to produce this simple plan for a 2′ x 3′ test module in short order.


Track Plan for the Test Loop.

Not much to it: a loop, a turnout and a spur. I had not purchased the product yet so I didn’t have track and structure libraries to work with; everything was done with the general features, tools and components. The color coding is to indicate wiring blocks; essential to using the test loop to work out block detection and other technical issues.

When I then laid the track I was able to replicate the plan exactly, down to the too-close clearance (to the edge of the module) at the turnout. I could have shifted the whole thing during build to improve the clearance but on this occasion the point was to reproduce track plan exactly as drawn without significant adjustments; and to see how it turned out. No surprises.

I had CadRail show the radius points for each curve on the plan (one of many view options). Locate the radius point exactly on the layout surface and, using a compass, you can draw the correct track centerline exactly where it is supposed to be. You can print a plan with grid lines and dimension measurements to help transfer the plan — if you want to sacrifice a lot of paper to the cause, you can even print in real size. Having struggled to transfer hand drawings with dubious calculations to real world materials in the past, this is a definite improvement. At $79 to download the full software and libraries, it’s a good deal  (for a bit more you can get a printed manual and CD-ROM installation disk, with a few extras to sweeten the deal. I went ahead and purchased the full monte).

Here is a view of the foundation for the loop.

test loop frame

It is a simple box frame, 2′ x 3′ x 8″, made from 1 x 2 and 2 x 2 poplar, with a 1/4″ oak plywood top (all from Lowes). In the past I’ve used common pine for benchwork. I chose hardwoods this time because I suspected they might work better for a modular system than softwoods, especially since I am trying to thin down the structure as much as possible while stiffening it as much as possible. Hardwoods are generally more dimensionally stable than low grade pines, especially in the smaller milled sizes. Furniture grade pine is good, but still not as strong as hardwoods and hard to get in my area. Hardwoods cost more, but for a small layout that extra cost is negligible. Poplar in the two sizes I’m using runs about $1 per linear foot, and is easy to work with. [Some poplar products are marketed as Sustainably Produced. I don’t know that is true with all poplar products.] The payoff is how much easier it is to keep your woodworking thin, straight and strong.

test loop frame detail

Corner Detail

I created a box frame with a top, not a fully enclosed box or box beam.  The joinery is simple lap joints with some mitered joints at the corners; nothing fancy or complicated. Brads held the frame together while the glue set (the classic Norm Abram technique.). I included a reinforcement bar under the plywood top; It is not absolutely necessary on a box this size though it did contribute to getting everything square and flattening the plywood.

I topped the plywood with 1 inch insulating foam. The resulting structure is light and amazingly stiff.  You can’t twist it easily; you’d have to push it past the breaking point to deform it. This is pretty much what I had in mind. I’m hoping that a substantial hunk of foam under the track will help suppress the mechanical sounds of locomotive mechanisms, which are not the sounds I really want to hear.

Finding a source of foam was more complicated than I thought it would be. The insulating foams sold for building purposes have changed over the years. Most are now faced with foil, paper or other additional materials. For my purposes, those extra materials are not useful. Then there is the whole problem of transporting 8′ x 4′ sheets of foam strapped to the top of the car and subject to easy damage.

Turns out that Owens Corning produces an unfaced foam product that is geared to the hobby market. foamular labelIt’s a dense foam that resists compression and holds pins very well. It comes in easy to transport and use 2′ x 2′ x 1″ squares. The only source I’ve found for it so far is The Home Depot, where it costs $5.48 per square as of this writing. I thought that was pricey at first and, compared to a full 8 x 4 sheet of building Styrofoam, is it is. But compared to hobby specialty foam products, it’s very reasonable at less than $1.50 per square foot for 1 inch thick stock; and I can get it locally.

Building with foams presents several new challenges. At the top of the list is finding adhesives that are foam-safe. Many caulks and adhesives will attack foam. Secondly, since I am joining dissimilar materials in many instances, the caulk/adhesive has to work with all materials being joined. Porous materials are usually easy; non-porous materials like most plastics are more difficult. Needless to say, I spent a fair amount of time at both The Home Depot and Lowe’s reading labels.

For adhering foam board to plywood I selected Loctite PL300 Foamboard Adhesive. This product is primarily formulated for adhering foam insulation to basement walls and the like, so once it takes hold it is strong.

Loctite PL300

I used about 2/3 of a tube to adhere two pieces of foam to the plywood; I think I can use less next time. Initial grab is mild, giving plenty of working time, but also requiring some sort of strategy to hold the foam in place until the product sets. I tried both clamping and screws: a few bugle-headed screws proved the best method for anchoring the foam while it set. I had a mild warp in one piece of foam that I easily straightened in the process. The holes can be filled or used for something else later.

roadbed trim and peel

Trim and peel test.

Liquid NailsNext I had to adhere cork roadbed to the foam surface. I bought some Liquid Nails for Projects then did a quick test to compare it to ordinary white glue. White glue will adhere to the foam, but it’s a weak bond easily broken. Liquid Nails provides a much stronger bond. As tight as the bond is, the adhesive does not dig into the foam so I could trim and peel off excess roadbed after the adhesive set without significantly damaging the foam.

Here is a view of the top, with the cork roadbed down.
test loop roadbed

Next up, laying some track, installing feeders and powering up the test loop.

Thoughts About Materials and Portability

lands end train setLike most (it seems) model railroaders in my generation, my love affair with model trains started with an HO train set under the Christmas tree at age 11.  I came to N scale years later as a married, working person prone to job changes and moving. It seemed to be a good answer to the problems created by my relative mobility.

So I took the plunge, armed only with knowledge of techniques common in HO. L-girder benchwork seemed the way to go, with cookie-cutter plywood subroadbed on risers topped by cork roadbed, followed by laced cardboard strips or screening to rough out shapes to be covered in paper towels soaked in plaster. You know the drill.

These were more or less mainstream techniques at the time, and they work well in HO and larger scales. But then, nobody envisioned HO layouts larger than a sheet of plywood as “portable.” For N Scale that is a bit of a problem because one of the attractions is the potential for mobility, a concept long ago proven out by N-Trak.

Traditional techniques meant that at moving time I had to trash the layout. Strip it of reusable parts and take the rest to the landfill. Bummer. I don’t think I ever actually “finished” anything because of this.

An Example of Traditional Benchwork from Model Railroader Magazine

An Example of Traditional Benchwork.

I found, after several tries, that conventional HO techniques do not always scale down well. Traditional “open grid” L-girder benchwork has no real structure other than support against gravity; traditional fascia is dressing and provides no structural support. To be portable, the layout has to be built on a box (see N-Trak “box beam” construction), which provides a rigid structure that lends itself to portability and opens up your options for supporting the box (any sort of leg system, L-girders, tables are all feasible now). For weight control we need to use thinner plywoods as well as thinner structural members than an HO modeler would normally use.

Homasote is an interesting material that has been used by modelers for a long time.  Today it is marketed as a sound deadening material, certainly a useful property for model railroads. In my area only a few building supply companies carry it, and only in 4′ x 8′ sheets.  From an N Scale perspective, the product is too heavy – the thinnest (and hardest to find) versions are 3/8″, making it useful only as a substrate material; in larger scales it makes nice roadbed.

An N-Trak Event (from

An N-Trak Event (from

I think I stopped modeling for a time largely because I was not satisfied with the solutions I had to the portability problem; and I came to loath having to destroy projects in progress. I find N-Trak too confining for me, especially since I don’t belong to a club and interact with other N-Trakers, though I thought about going that direction for a time.

T-Trak Base Module

T-Trak Base Module

T-Trak seems to improve some on modular railroading generally, and it is theoretically scale independent, but because it is designed to be used a certain way to ensure interconnectability, it is inherently confining. I need a more generalized method for building any style N-scale layout in a modular fashion.  The theory is that any sort of layout can be broken down into portable modules with the right construction techniques.

Since my last layout, the use of styrofoam and other insulating foams has become mainstream, as have a wide variety of alternative materials. Adhesives are replacing nails and screws. Lightweight wood structure with foam as the scenery base looks like a promising way to achieve my portability goals.  I’ll try it out on the test loop.

First Things First

The first job was to unpack and survey my models and supplies. I already knew we took a loss a few years ago when a box of stuff got crushed. A couple of locos and a bunch of rolling stock are gone for sure. I hadn’t had the heart to check the rest until now. What is it they used to say in the Army? Three moves are as good as a fire.

Thankfully the good condition of the remaining boxes did not hide a disaster inside. My Kato 2-8-2 Mikado, just purchased, not yet detailed and barely tested when last packed 15 years ago, is in perfect condition.

Kato Mikado

My much abused Trix 0-6-0 is still with me and in need of several repairs which I hope to attempt when some material gets here from Micro Mark. A flea market Bachmann U36B looks like it should run though it won’t fit on a transition era layout.  No matter.

The built structures survived, mostly, and the kit collection is ready to go. I still have some unused track collected 15 years ago for another layout that was never built: 25 pieces of Peco code 80 flextrack and 7 unused Peco Code 80 turnouts, and one wye, are a very good start. I may play with some code 55 for sidings, branch lines and the like, but I think I’ll stick to code 80 otherwise for this go.

It’s been a while since I had any space available. Basements are not all that common in Reno (tough ground to dig for starters), and it seems that carving space out of a bedroom or garage is always impossible. Our current home has a basement; but it is all pretty much in use as living and working space. The utility room is actually a substantial space; finished out as recreation space with a classic 70’s vintage bar area, and cheap wood paneling everywhere. We use the room for storage, and floor space is lacking because of that. A substantial layout is impossible without moving all the storage elsewhere, and as renters that’s probably more layout than we’d want to contend with anyway.

But then, thinking differently, I started looking at the bar as an opportunity:

Layout Space

It’s difficult space for obvious reasons. Low headroom, no light and you can see from the picture that getting light in there will be challenging because I have to take the space as it is. No modifications to the space allowed.

On the other hand, the bar is a perfect table/support for a layout. The surface is a generous 82″ x 66″ L, 27.5″ wide all around. Its almost completely walk-around. This is a doable space for N scale. The counter is 40″ off the floor, which I think is a good height to work from. I won’t need a a leg system for setting up on the bar; setting up the layout in other locations will require portable tables or some other support. I have a concept for separate, portable support loosely based on L-girder design. Perhaps in the future, but for now I’m going to embrace the bar, so to speak.

So this was my first time ordering from Micro-Mark. Remember how I said that I have to be able to get materials locally or online within a week? Well, forget that one with Micro-Mark. It was only after finding some items for the shopping cart that I discovered that their policy is that it takes 2-3 days to prepare a shipment. No 1 business day turnaround here. And the choices for shipping methods leave much to be desired. Hmmm. Having not shopped for hobby supplies via the Internet before, I don’t know what the norms are for this sub-industry. I’ve already received a small order from Digi-Key placed on the same day. I’ll let you know what I think of this experience after the goods arrive.

That prompted me to grab my wife and trot over to our local Michaels in search of quilter’s T Pins (Woodland Scenics markets a version of these as “Foam Nails”) and to conduct a stock survey. Michaels is a quirky place, but they are well set for the basics: glues, art supplies and tools, and a wide range of jewelry making and crafting supplies. Maybe I won’t be as dependent on Micro-Mark as I thought.

I should note that Reno used to have a well-stocked hobby store that was primarily rail oriented. The other stores here focus on other hobbies like R/C and Military modeling. The owner of the rail store was older and looking to retire some years ago and I think he successfully sold it. The store did not survive the Great Recession, however, so specialized model railroad support is lacking here. Having lived in Baltimore MD for a time and worshiped at the shrine of MB Klein while they were downtown, I have very high standards for a Model Railroad shop. For better or worse, I’m largely dependent on the Internet for parts and supplies.

Anyhow, having unpacked and done some basic organization, the first order of business is to create a test loop; well more than that really, a test module where I can do a first test of some intended materials and techniques including eventual turnout and block detection systems. Right now, I need to test the locos and rolling stock and find out what needs to be fixed or replaced.

I’ll tackle that next time.