L&NC Construction Update

It was a nice day to take the lower level outside and transfer the track plan.

It was a nice day to take the lower level outside and transfer the track plan.

After the box frames were built and topped with 1/4″ plywood, I started in on building up the lower level. Because of the limited vertical space between the levels, I limited the thickness of the foam layer on top of the plywood to 1/2″, using a Styrofoam sheet product I found at Lowe’s. This type of Styrofoam is not ideal (I prefer denser foams) but its what I could get cheaply in 1/2″ thickness.

I’m using the Woodland Scenics foam pencils that work great on dense foams. This large cell Styrofoam is fairly soft so you have to use a light touch with the pencils or you’ll end up with grooves instead of lines.

Is a Plan Ever Done?

L&NC Lower Level, Version 2

L&NC Lower Level, Version 2

It shouldn’t surprise anyone that I’ve been tinkering with the track plan.  Since I first transferred the track plan to the lower level, I’ve added additional storage / sorting tracks at the Red Bluff Yard (I’ll draw that in before laying the roadbed). At Melville I added a short branch track to serve a local merchant; I have a neat little covered depot kit I intend to use for that feature.

As you can see from the actual module above, the Roundhouse and turntable in the drawing don’t accurately represent the  arrangement. The roundhouse I rebuilt is designed for a much larger turntable than the one shown in the drawing — 120 scale feet. There was no upside in trying to accurately draw it in CadRail, so I used a library object as a placeholder. The library object is a roundhouse / 75′ turntable combination.

The Helix

The middle module has only a little track but is all curves.

The lower level of the middle module has only a little track. The spiral intersection of the two tracks isn’t right yet.

After drawing the lower level track plan on the foam on the left and middle modules, I turned my attention to the third module.

That one contains the West Helix. Not much to draw on the foam. Not much, that is, except the critical diagonal tangent from the helix to the curves on the adjoining module.

I couldn’t draw in final track lines without having the helix ready. The helix is the primary feature of the lower level. It was designed to fit the space tightly to accommodate a 12″ radius curve, so it made sense to build the helix first and fit everything else to it.

Here is what I whipped up in an afternoon:

The helix basic structure.

The helix basic structure. Those rods will poke your eye out if you aren’t careful! I cut off the excess at the first opportunity.

I made the helix from a set of arcs, 2″ wide with a 12″ radius center line, cut from 1/4″ plywood. Each arc is 240 degrees, or 2/3 of a circle. This kept the number of joints down and made sure they were staggered. Using plywood plates to join adjacent arcs, I put enough together to make the helix. When the glue was dry, I screwed eyelets into the sides of the plywood ramp, inserted 1/4″ threaded rods to act as supports, then raised the helix using  nuts to hold the eyelets in place. You can see the result above. When I was satisfied with the positioning of the ramp, I froze the nuts in place with a little CA.

Final fitting required having the top section in place.

Fitting the helix between the two levels.

Fitting the helix between the two levels of module 3.

While fitting the helix, if found that the softness of the Styrofoam the helix supports were resting on was going to be a problem. I had been thinking the nuts at the bottom of the rods would spread the load sufficiently, but that proved not to be the case.

My solution was to glue little plywood pads in the places where support rods would contact the lower level. I also glued in a transitional ramp to connect the bottom of the helix to the lower level track.

Pads for support rods, plus the connecting ramp for the bottom of the helix.

Pads for support rods, plus the connecting ramp for the bottom of the helix.

A Little Track Laying

With the support in place and the helix fitted, I decided to go ahead and lay the track so that the helix was completely ready to go.

Having the helix as a free standing object made access and track laying so much easier than it might have been.

I added feeders every 18″ or so. The whole helix will be a single block and the last thing I want is power problems! While I was at it, I fastened a string of addressable RGB LEDS to the underside of the plywood, spaced at 6″ intervals, so that the helix can be lighted.

Helix with track, ready for use.

Helix with track, ready for use.

Underside of the helix.

Underside of the helix.

 

 

 

 

 

 

 


After thoroughly cleaning the track I tested a locomotive on the helix and it ran well, so I’m confident the helix ready. Now I can finish drawing in the lower level track and move construction on to the next phase.

 


 

L&NC Construction Underway

Lassen & North Coast RailroadConstruction of the Lassen & North Coast Railroad began in earnest with the construction of the three box frames for the layout.

The L&NC is intended to be a portable layout consisting of three modules that will individually fit into the back of a small to mid-sized vehicle, including crating material. All three modules should fit into a larger vehicle, such as an SUV or Van. To do this, I’m building a foundation that—for lack of a better term—I call a “box frame.”

Most benchwork is done in the L-girder style if the layout is permanent or in a box style if portable or modular.  I’m building a variation on the box theme, so that it can be both portable and include two levels. Each module consists of an upper and lower frame, joined together at four corner posts. Both top and bottom frames are topped with a piece of 1/4″ plywood.  This approach should help keep weight down while making the structure rigid.

The trick for this layout, of course, is to get three two-level modules to fit together securely so they can be taken apart for work or for transport, then put back together again reliably. One level is easy enough, but two levels?

Building A Stable Foundation

After cutting, milling and drilling all the frame members, assembly begins.

After cutting, milling and drilling all the frame members, assembly begins.

I decided that the way to pull this off was to prepare the necessary lumber for all modules at the same time, then put everything together at once to guarantee fit. I chose poplar from my local Lowes instead of pine. While more expensive, poplar more than makes up for it with its straight grain and hardwood strength. For joinery I decided on lap joints; more glue surface and thus more strength than simple butt joints, but easy to do. I like to follow Norm Abram’s methods and pin all joints with brads during glue-up.

My small collection of shop tools made this part easy. I cut all the pieces to length on the miter saw, using stop blocks to cut multiple pieces of the same size.  Most frame members are made from 1 x 2’s; I used 2 x 2 poplar for the corner posts. Then I taped frame members of the same size and type together (see the image above) and, with a dado blade in the table saw, cut the lap joints at the ends, and dadoes for cross members, in the frame members.  Then, at a small bench-top drill press, I cut holes in pieces intended to be used as internal cross members to facilitate wiring and other needs.

The last piece of preparation was on frame members of adjoining modules; these connect to each other when the layout is assembled. Preparation of these pieces required the installation of an alignment system that guarantees the layout comes back together consistently.

Aligning Modules

Installing McMaster-Carr alignment pins & liners

Installing McMaster-Carr alignment pins & liners

I use alignment pins from McMaster-Carr for aligning adjoining modules, choosing the 3/8″ diameter pins and matching liners. The fit of the pin into the liner is precise, and will bind if you attempt to force them together at the wrong angle. On the other hand, the rounded ends of the pins help guide insertion which, if the angle is correct, is smooth as silk.

I configured four pairs (two pair for each module interface) of frame members to butt against each other with the pins for alignment. Each pair was taped together, I marked center points and then drilled and countersunk on the drill press. Actually, I countersunk first on both sides of the taped pair, then drilled the smaller through-bore. I use Forstner bits for this kind of thing, because of ease of centering and the clean bores those bits produce.

Installing corner posts to join the top and bottom frames.

Installing corner posts to join the top and bottom frames.

After gluing up the top and bottom frames of the first module, I set the corner posts that were dadoed to fit into the frame corners.  As you can see, the posts form short legs for the module in addition to supporting the top frame.

For the top joint, I created an ersatz mortise and tenon joint to hold the top when installed. To do that I set the top frame on top of the posts, then glued blocks to the frame around the “tenon” to form the mortise. The mortise and tenon joint created is snug; This joint is intended to come apart, so I eased the top edges of the tenons to make assembly/disassembly easier.

Module #1 fully assembled.

Module #1 (the “eastern” module) fully assembled.

Here is the fully assembled first module.The near end abuts the next module; the matching member for the lower box is mated with the assembled module to test fit.

Test fitting the three module frames.

Test fitting the three module frames.

Next the middle and right hand modules were built, then the whole thing was put together to test fit and the alignment system.  Thanks to the McMaster-Carr alignment pins, and careful assembly making sure everything was aligned correctly every step of the way, the frames came together correctly the first time! I can’t emphasis enough how important it is to take your time, constantly testing and retesting fit of key components, when doing this kind of framing.

At this point the western (or right hand) module is only partially framed. When I put together the helix intended for that section, I found I needed to make a few modifications to the upper frame to make it work.  I’ll get into that in a subsequent post.

Drilling for and Setting Retention Bolts.

Drilling for and Setting Retention Bolts.

In the meantime, the last step in basic construction was to create a fastening system to hold the modules together when assembled. NTrak and other modular systems generally rely on C clamps.  On this layout, given its design intention to sit on top of a bar (or tables), C clamps are a bit awkward. So I chose 3″ machine screws that connect with 4 prong tee nuts (often used in furniture making).  After clamping each connecting pair of posts together, I drilled the hole then set the tee nut on one side to connect with the bolt inserted from the other side.

The modules fit together well enough that it is not generally necessary to use the bolts to pull modules together. The bolts with the alignment pins make a solid connection that can be assembled and disassembled easily.

With the basic frames complete I topped the eastern (left hand) and center modules with plywood. I also put 1/4″ plywood atop the lower frame of the western module. The upper frame of the western module will need more work to accept a helix.  That project, and general build up of the layout are ahead.

With much to do, I’ll pick this up again in a subsequent post.


 

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.

document

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 ntrak.org)

An N-Trak Event (from ntrak.org)

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.