Foam Board

a) On a small, portable layout, just add layers of foam. You could use Woodland Scenics foam risers between these and the base. O'wise, calculate the elevations at 4" to 8" intervals, and glue risers (small blocks of foam) at those locations. You'll have to slope the top of the riser slightly, but that's easier than sloping a long piece of foam. Use the shorter span for 1" foam, and the longer for 2" foam. BTW, your track should not be laid directly on the foam. Use cork strip between the track and the foam, even if you use the kind mounted on plastic ballast former.

b) Medium sized layouts (up to about 4x8ft) can be built as above, or else fully supported on benchwork.

c) On a larger layout, you lay the track on track boards (subroadbed) mounted on risers which are fastened to the L-girder or boxframe forming each section of layout. The foam is used mostly for scenery.

Well, actually you do have to build some benchwork, but it can be a lot lighter. A shelf layout for example can be supported on shelf brackets, with the foam supported on or inside a boxframe made of dimensional lumber or light plywood. I used 1x2 to make a boxframe for a 24"x30" proof-of-concept N gauge layout recently. I glued 1/4" luauan plywood to it, and glued a layer of foam to the plywood. The track support was a double layer of foam cut about 1-1/2" wide (I'd use 2-1/2" to 3" for HO). The glue was acrylic latex contact cement (water based). Then cork was glued to the foam, and the track to the cork - I used pins to hold it in place until the glue held.

If you use a boxframe, you just drill a hole and thread the wires through. MR showed a neat trick recently: push a wide straw through the hole in the foam, thread the wires through the straw from above, and then pull out the straw from below. You can also cut grooves for the wire to lie in alongside the track base, etc. Be careful with your soldering iron around foam - it can melt a big hole pretty quickly (and the fumes are toxic.)

If you are building a micro-layout, bring the wires out to the side. I've seen such layouts framed with plywood all round, 1/4" is strong enough for mounting things like switches and plugs. (A micro layout is about 8 square feet or smaller: a really samll one can be built on a

2"-4" slab of foam with any further support.)

HTH

Thanks for the info there, Wolf. I've worked with L girder construction but I was thinking of going to foam for this smaller layout I have in mind.

I was looking at those Woodland Scenics Risers, and they do look pretty convenient, but how do you slope the top of the Risers to get a grade? Like going from 0" to 2" in four feet or whatever. What do you cut them with?

Well, you could put a yardstick on each side and use the hot wire foam cutter to cut them along the edges of the yard stick...

But it would be easier simply to buy the risers that are already cut as grades. I know they have at least 2% and 4%... I think they've got 1% as well.

Make a template for the angle, and use a kitchen knife before you glue them in place.

Place a 4% on top of a 4% and you get 8%, 2% plus 4% = 6% etc. With 1% risers you can get every 1% step from 1% to 180% ;-)

Greg.P.

i> A few questions for those of you who have layouts on pink insulation i> foam board: i> i> 1) How do you handle the elevated track areas? Do you glue more foam i> on top and cut it with a hot wire cutter into the grade that you want? i> It seems like doing that would be a bit of a pain. Any tips?

I'd use a sure-form tool, but otherwise yes you add foam and carve it to suit. Yes, the sure-form tool creates a lot of mess, but that is what your shopvac is for. The shreds could possibly be used as loose filler. For major foam removal a serrated bread knife works well. One can fine tune things with other 'abrasive' tools: wire brush, sandpaper, etc.

i> i> 2) What do you put the board on? It seems like one of the advantages i> to using foam board is you wouldn't have to build all that benchwork, i> but if you just slap it down on a card table or sawhorses it's not i> going to be closer to eye level which looks better. Also, how do you i> handle all the wires coming out through the bottom of the board i> (related to what you set the layout on)?

You still build the benchwork. It is just a lighter weight benchwork. You use a *lightweight* (sparse) 1x4 frame under the foam. Much of the weight of a 'traditional' benchwork was with the plywood and the relatively 'dense' framing needed to support the plywood. Because the foam is actually *more* rigid than plywood (assuming the thinner

1/4 or 3/8, rather then the thicker 1/2 or 5/8), you can use somewhat wider joist spacing. Warning: you probably want to avoid too much 'heavy' scenery, since the benchwork is not as strong as with the traditional heavy plywood type benchwork. You run the wiring, etc. under the foam, as usual.

i> i>

\/ Robert Heller ||InterNet: snipped-for-privacy@cs.umass.edu

|| snipped-for-privacy@deepsoft.com /\FidoNet: 1:321/153

But you are actually adding angles, rather than the tangents thereof. It won't make much difference at reasonable grades. Ten 1% wedges stacked equals 10.7% grade. The error would be less with fewer larger wedges.

But a 180% grade is 61 degrees. 180 1% wedges would be 103 degrees. That is only slightly upside down.

Sorry, I'm used to the more sensible system of measuring gradients in ratios like

1:100, 1:50, 1:25 etc. My mistake.

[...]

Not more sensible, just what you're used to. I have to translate "1 in

30" to "a little over 3%" to make sense of it... :-)

Jason Davies wrote: [......]

Thanks. I'll remember that when I build my roller-coaster layout ;-).

-- Kizhe

Take a look at this (bottom photo of page):

Daniel Lang

Oops I goofed with the first post!

Actually what I've done is to use a door as the bench work. Then I "cookie cutter" my subroadbed shape into the foam layer (I use 2" foam). Between the foam layer and the door benchwork I place a series of shims in 1/16" increments. The foam maintains a smooth gradient that also transitions smoothly since it is always 2" thick plus whatever the shims are. For a 1% grade the shims change every 6 1/4" for a 2% grade every 3 1/8" etc. The foam is rigid enough to handle these spans especially since I bond 1/8" door skin to the top of the foam so that the resulting structure will hold track nails. I like to use track nails because I find that I tinker with the track plan quite a bit before I get to scenery since I do not have the patience to come up with a rigid plan before commencing construction.