What are the best materials for supporting a foam based layout.

[LV LOU]

I'm on my third all foam railroad,had the last one over ten years before I moved,never had any problems with it...I don't use anything under the foam,just benchwork.I don't really even go nuts mounting the foam to the framework,it's glued only at the walls and the middle of the island,so the wood doing stupid things isn't a problem.I put a few deck screws on the outer edges just to keep it down,but in foam,they hold it,but it can still move if the wood expands.The sides are 1x4's,and there are 1X2 stringers running across 16" on center..On the island,since I wanted to support it in the middle and end only to keep the aisles clear of legs,I put 1X4's up the middle,notched for the cross braces.I've never had any kind of problem with warping,sagging,ETC,and if not for the fact that I'm a pretty big guy,and I really engineered it to be light,and have very few,light legs,I'd have no second thought about the actual platform holding me.The island is over 4' wide in spots.It's actually been changed quit a bit since this pic was taken,that grade on the left joining the top/bottom mains is gone,the right side of the island is totally different.

[OldEastRR]

I'd say the minimum use of dimensional lumber is state of the art (at least in N scale -- full wood solid plywood benchwork was originally designed for heavy O gauge locos and masses of plaster/wire scenery, not to mention tons of wiring, relays, etc). Use just enough for a basic support of open framework: sides, widely-spaced cross members. Maximum use of extruded Styrofoam is state of the art, definitely for "layers" of scenery, optionally for track subroadbed. Grades are not a problem if you think of the sheet as a board. You don't shave down plywood subroadbed to adjust the grade, so why do it with foam? Incline the track subbase by gluing cut-down foam block "risers" to your framework and set the foam grade on them. Foam thinner than 2" is best for this application. Masonite or pegboard securely glued to the bottom of the foam provides an anchor for wiring busses, switch motors, signaling circuitry, etc. It doesn't need to completely cover the base of the foam, either. A wide ribbon of Masonite can serve the purpose.
For design, state of the art would be sectional construction (not to be confused with modular, a whole different animal). Sections that, with legs removed, can fit through regular doorways. You may think you're never going to move again, but you may be wrong. Taking apart a sectional layout is much much easier than one built as one solid chunk. Other advantages to sectional layouts is the parts can be removed and worked on (or modified) at the workbench or an open area.
For stability, there doesn't seem to be any reasonable alternative to fastening the benchwork (or part of it) to a wall(s). Free-standing layouts or peninsulas of fixed ones need a lot of bracing to prevent wobble and shimmy when bumped. Even bolting the legs to the floor doesn't eliminate the range of swing at the top of the leg -- right at layout level -- to horizontal forces.

[rogergperkins]

Great examples of use of extruded polystyrene foam.

[DKS]

The White River and Northern IV was also a 100% foam layout. Overall size 7' x 10'. The base was two 2" layers laminated together with Liquid Nails, just resting on 1x2s attached to shelf brackets. (Not too far removed from Ed's benchwork style, just a lot more robust.) Fascia was foamcore with woodgrain self-adhesive vinyl applied. The black stripe is Velcro to hold throttles, small tools or test equipment.

[robert3985]

"State of the Art" is probably an opinion because the needs of the N-scale layout builder differ considerably from one person to the next.  All of the preceding methods work well for those who've built their layouts, and who's gonna tell anybody their methods suck??  Not me.

My own definition, and what my benchwork has evolved into fulfills several purposes, which are:
(1) Made from common materials easily purchased at home improvement centers and/or lumber yards
(2) Made from materials that allow simple drilling, gluing and screwing of all joints for permanence and stability
(3) Made to be robust so that transportation damage will not occur by normal transportation methods (throwing in the back of my Suburban and a U-Haul trailer)
(4) Light enough so that I can set them up and move them around by myself when the shows are over and they're stacked in my train room
(5) Light enough so that two 15+ year old teenagers can carry them easily (my sons...who are now 26 and 27)
(6) Integral folding legs for ease of setup, breakdown and transportation and stability when layout section is standing by itself to be worked on separate from the layout
(7) Robust and stable ends which bolt to each other to form my modular layout
( 8 ) Removable skyboards
(9) Robust flowing front fascias

Took me a while to finally get the right combination of simplicity, materials and construction techniques but this simple illustration is the result (minus folding legs, roadbed and risers).

Pic 1  Barebones twin L-girder benchwork:


Materials for my use are premium pine boards (straight, don't warp, and can accept screws in the ends), with 3/4" sanded-one-side plywood for the ends.  The skyboard is 1/8" Tempered Masonite, and all joints have clearance holes drilled first, then glued and screwed with square drive grabber screws.  The clearance holes allow the boards to be tightly clamped by the grabbers.  Simply drilling the grabbers through both pieces doesn't work that way.

What isn't shown here is the two-layer 1/8" laminated fascia, which I never put on "straight".  I always curve or "flow" it so it's not parallel to my mainline's course except at the very ends.  This fascia is extremely sturdy and the modules can be lifted easily by it and moved around.  I put the fascia on before I build my subroadbed, but my entire LDE has been drawn in Cadrail by this time, so there isn't any guessing as to where the rails and scenery are going.

As to subroadbed.  I use laminated (splined) Masonite subroadbed held in place by risers, which are attached to redwood 2X2 baluster cross-braces glued and screwed to the tops of the my L-girders.  The 2X2's can serve double-duty as riser attachment points and supports for the fasica.  To cut down on complexity and weight, I design that into my benchwork quite often.

Here's a photo of my Emory Center Siding module after the subroadbed has been attached.

Pic 2  Emory Center Siding Module:


I've also built the same twin L-girder benchwork and attached 2" extruded Styrofoam to it as both a scenery base and subroadbed and those modules are in operation as part of another modular groups setup.

For me, the twin L-girder design is extremely versatile as well as robust.  It's also simple and for a home layout, I'd build my layout in 6'sections with the 3/4" end-plates, bolt them together and gap my track at those points so if I ever needed to move, I could simply cut the scenery with a box knife and separate the 6'sections.  Oh...and use Anderson Power Poles at the section joints for easy wiring separation, or "droop" your wiring there so if you need to separate the sections, you've got enough wire to either strip insulation and solder 'em back together or apply Andersen Power Poles to make any future move easy.

I'd also make sure that I used sturdy glides on the ends of the legs screwed into T-nuts with a locking nut to tighten them up when you get your layout perfectly level.

I prefer to keep my 2" extruded Styrofoam scenery base off the layout until I've got all the wiring done.  It's a helluva a lot easier to do it from the top than crawl around underneath like you have to do with HCD based benchwork or sheets of extruded polystyrene, or even cookie-cutter plywood benchwork.

The reason I went with the splined Masonite subroadbed is because it's about the most thrifty AND robust way of making subroadbed.  The only waste is the kerf and in N-scale, you can get a lot of subroadbed from a couple of 4X8 sheets of either 1/4" or 1/8" Masonite.  I use 1/4" when there's not a lot of curving going on, and 1/8" for sharper curves.  I glue and clamp my splines with yellow carpenter's glue and a whole bunch of C-clamps and spring clamps.  It goes pretty quickly, and you can do it yourself, but having a buddy helping really speeds things up.  I also have a local mill cut the Masonite for me into 1" strips.  Cuts down on the dust and they do a better job than I can because of the long, unwieldy sheets.

Although some modelers think what I build is overkill, I'd rather err on the side of being too robust than not robust enough, especially with my hand-laid trackage and modular concept.  I don't want sagging, warping or twisting to ruin my trackwork and so far, that hasn't happened.  I live in Utah, so the humidity is very low.  If I lived in another more humid clime, I'd seal it, or use steel studs for the L-girders.

I love benchwork as it gives me an opportunity to use my woodworking equipment.  For me, it's more like cabinetry than merely slapping together something from scrap I've collected at several construction sites during the Winter.  Building a stable base for your trackwork is essential IMO.

[Philip H]

I love benchwork as it gives me an opportunity to use my woodworking equipment.  For me, it's more like cabinetry than merely slapping together something from scrap I've collected at several construction sites during the Winter.  Building a stable base for your trackwork is essential IMO.

I couldn't agree more.

Except this time I have the "luxury" of having acquired most of my benchwork for free off Craigslist.  So I'll use my wood working skills on other parts of the room.

[rogergperkins]

I have limited skills and only basic tools, so when I built my current layout, I had help from a person who brought his table saw and hauled the sheets of plywood and foam to me.
Thanks for all the comments, you have given me some wonderful examples.
The layout I am planning will be accessible from all sides, hopefully in a basement area large enough to have my home office
in the same location as the layout.
 

[C855B]

... some modelers think what I build is overkill ...

It is. I have a 6-ton truck that could safely drive over that. 

[LV LOU]

It is. I have a 6-ton truck that could safely drive over that. 

Wow..You ain't kidding..To me,that's way overkill for G Scale..Well,to each his own...

[randgust]

The only two cents I'll throw in here....

My benchwork reflects that saying that 'when the only tool you have is a hammer, every problem looks like a nail'.

My father the lumberman left me with a very nice wood shop, way back in the 70's.   And there was always more than enough scrap lumber from his workshop projects to make anything I wanted to build.    You'll find scraps of some fine exotic hardwoods in old benchwork of mine.

Way back in the 70's I was building cookie-cutter with plywood and good pine, put together with screws and glue.  The point of that is that those of you at Bedford saw the Hickory Valley portable layout and I made that back in 1975. It's been all over the northeast, dropped down a flight of stairs, and has generally been abused and lived to tell about it.   

I'm still building that way.  No foam for me.  I watched a lot of nice layouts literally fall apart over the years, many which relied on homasote roadbed.  Now there's something you won't see much of anymore, and for good reason. 

The only thing I can add to what I've seen is a plea to all the guys using wood or fiber material, please - take the time to put on a good coat of latex paint to lessen the seasonal expansion and contraction, particularly if you live in an environment like PA that has 80% humidity in summer (with a dehumidifier running) and 50% in the winter (with a humidifier!).  And it exists, let me tell you.   All that wood wants to move, a lot.  I've painted every single stick of plywood and wood on all my layouts for 30 years, and its worth the work.  All surfaces.   If you don't want track and table joints popping in the future, that's the best thing you can do now during construction.

[DKS]

I have limited skills and only basic tools, so when I built my current layout, I had help from a person who brought his table saw and hauled the sheets of plywood and foam to me.

Something to be said for hollow core doors, in consideration of this. Attach some folding legs to each door, connect them together with a 1 x 6 splice plate underneath and a bunch of screws, and you're ready to rock and roll. No table saws, no killer sheets of plywood. Food for thought, anyway.

[ednadolski]

Here is what I did for my little Tehachapi Loop layout.    This is basically a flat plywood substrate made from 1/4" plywood sheet and 3/4" plywood framing.  The sub-roadbed is also 1/4" cookie-cutter plywood, glued atop Woodland Scenics foam inclines.   This is probably a less common method, but it is lightweight and it has held up well for about 8 years now, with no warping, cracking, or issues with the track.  That includes a move to a new basement with virtually no damage.



Ed

[JoeD]

My good friend, Scott Mangold built his room size layout (featured in N Scale Mag awhile back) using cardboard for the benchwork.  All laminated from old boxes.  The only wood is the horizontal supports that tie the modules together and of course the legs I believe.  His layout is world class and has components built over 30 years ago.   So, what is state of the art...I guess what ever meets your operational requirements and is within the limits of your engineering skills.   Another old friend of mine made his HO layout using only 2" foam laid on braces attached to the studs in his wall.  No sub bracing other than a 1/8 plate epoxied and screwed to the edges of the sections to joing them together.  The material is ridged enough with limited support to give you a very substantial base...absorbs sounds and can be transported with very little effort.  I've been down the route with mega carpentry and I think there are a number of lightweight materials that deserve a second look.

[basementcalling]

Good benchwork is like an umpiring crew. It should never draw attention to itself after construction is done just like you never notice umpires and referees that are doing their job at a high level.

If benchwork is an issue once track laying and scenery begin then it wasn't state of the art.

[randgust]

Well said.   But there's another corollary to that one as well....

If the only reason the railroad was torn down was because the railroad couldn't be moved.... it's not state of the art benchwork either.  I haven't always had lots of reasons to line up on Robert3985's side of the field, but I sure willl there.  My first HCD layout (which made RMC) had to be torn down because while the door barely made it in the room on edge, the layout was never leaving that way - it had to be destroyed.  So the current ATSF layout was designed as six bolt-up modules, with no module wider than 27" and longer than 48", pretty much looking like his design.   It could fit through a door upright, on its legs.  And that was '83.  And it survived three moves to three states since.    I'll tear it down when I want to, not when I have to.

Now mind you - that battleship construction is also why a layout can live long enough to have problems like legacy track!

Another thing you'll run into on stand-alone layouts built to the 52" height is the distinct potential that you can cause significant damage by falling/leaning into them or, into the case of a duckunder, coming up too soon.  I deliberately designed my modules to function as shelving under the layout, for books and materials.  She ain't moving with all that weight on it.  If you come up too soon in the duckunder, you'll take a lot more damage than the layout.