Foam Board Thickness 1 inch or 2?

[Bobster]

Greetings all,

So I'm finally going to start building upon my 36" X 80" door.  My question is above. 
Do I use 1 inch thick pink/purple foam or 2 inch thick for the base?
What are your thoughts on which to use?

Some background. 
My old 36" X 48" layout was 3/4" foam and I never really got enough depth for a decent creek.  I'm planning a double track oval with a stacked foam low river bluff on the back edge left side. There may be a sandstone cliff to the right end of the bluff.   The track will not be parallel to the table edge but angled with the left end being towards the front and the right end being towards the back.  There will be spurs serving industries in the interior of the oval.  The feeling I'm aiming for is a small town in a valley in the midwest.  Some kind of cross between Rock Island RR's Bureau Junction and Santa Fe's North Chillicothe in Illinois.  EMD GP's and E units and ALCO FA's will be the motive power.  Turntable and round house will still be present.   I will not be showing any of the river.  Plan is for the 1950's but possibly later as the mood strikes me.   On the other end of the plan I have the Peoria and Eastern, a Wabash Cannon Ball, and a Pennsy Doodlebug.   

Thank you for your comments,
Bobster

[nickelplate759]

Since it's on a door, the foam is only as a scenic base, not structural, correct? If that's true, then you just need to think about scenic elevation. Consider what you want to have below your base grade.

1" in N-scale is about 13'  That's enough to allow your track to go over a creek, but pretty tight (although not out of the question with the right kind of bridge) if you want it to cross a roadway.  It's really low if you are crossing a river, unless the river is running high at the time you are modeling it.

My hunch is that 2" is more than enough, 1" may force you to make some compromises - or you can use 1" and raise the roadbed a bit (at least 1/4", maybe 1/2").

[thomasjmdavis]

I did a layout section 20 years ago that used 2 layers of 1 inch foam instead of a 2 inch piece.  I had a river running through that section of the layout.  The riverbed was the plywood (I was using framed plywood rather than a door, but similar concept) and the first sheet of foam was the "riverbank" level with the second piece forming higher ground set back from the bank.  The mainline came across the "high ground" on a slightly elevated embankment so that a spur serving dockside warehouses on the lower foam level would have enough clearance under the plate girder bridge that served as the approach for the main bridge.  The river "East" of the bridge was the "Lake Michigan" side- any ship that did not clear the bridge stayed on that side.  The plan was for the lower spur to cross the river via a bascule bridge, but had to move before I got that far.

[pdx1955]

I would lean toward multiple layers of 1" for the base as 1" is easier to work with. If you end up cutting the banks with the top 1" piece and gouge into the bottom layer for a bit more depth you'll have the best flexibility.

[Scottl]

Foam also comes in 1.5" sheets.  But any of them will do.

[MVW]

I've found the 2" sheets usually have "waves," probably caused by pallet straps. The 1" foam is usually much closer to flat. As a result, I've switched from 2" to 1" unless I need the depth for scenic purposes.

Jim

[nickelplate759]

I've found the 2" sheets usually have "waves," probably caused by pallet straps. The 1" foam is usually much closer to flat. As a result, I've switched from 2" to 1" unless I need the depth for scenic purposes.

Jim

Good point!  I used 2" for structural reasons (no plywood underlayment), and have exactly this problem. I've spend far more time than I wanted to leveling it.

[Dave V]

I used 2" on the Juniata Division so I'd have enough clearance for this scene:

[thomasjmdavis]

+1 Dave V.  If it weren't for CMW auto I might not have recognized that as a model.

[Bobster]

Good morning all,

What I love about this forum - the wisdom of others helping me get outside my perspective.

Let me see if I can cover all the responses.

It looks like most of your responses favor stacked one inch foam boards to the needed height as the better alternative.

I forgot to mention this will be a DC layout for the time being.  I don't have the time or money right now for DCC.

The door will be the structural part the foam will be the base.   With the stacked foam bluff being higher in the back and then a gradual perceived down-slope towards the front.  I had not even considered actual below grade opportunities at the front.  To clarify, my original plan was going to be the foam rail-bed at all one level.  The foam bluff would have a perceived cut at its base for the tracks at the layout back by stacking thin layers of cork or foam on the inside of the loop.  The stacked layers would get thinner as I moved closer to the front of the layout.  Thus Main Street would run slightly down hill from back to front.   With your thoughts in mind the planned creek to the left would have more space to drop and I possibly could have Main Street go under the track at front center rather than at grade crossing.   

Now let me toss out another thought.  Since my Main Street will be close to three inches wide what would be your thoughts be on running the feeder wires in a narrow trough under center two lanes of Main St. and the cross streets?   The transformer will be somewhere on the front right side of the layout.  There will also be a 3 stall round house to the left, inside the double tracked curve.  Or should I just get a long drill and run all the wires under the door?   I'm not as young as I used to be so something easy access and from the top is my inclination.  Any better alternatives?

Thank you very kindly for your support,
Bobster

[pdx1955]

It would be easier to just drill holes where needed instead of trenching especially if you decide to change or add more feeders in the future. You could make all of the connections along one edge for easier maintenance - use of suitcase connectors will speed things up. Since it is a door layout you could just flip the whole thing on its side and make quick work of the electrical needs without having to do the crawl underneath.

[Bobster]

Dave,

Beautiful work.  How much foam is below the creek.  Are all your hills and valleys on a stacked foam base?  As I recall you built on a hollow core door.  I wish I would have paid better attention over the years.  I do not recall seeing pictures of the JD under construction only finished pictures.

PDX1955,

I can see what you are saying for the lower elevations.   I'll have to see about the buildings on the bluff tops, is any.  Maybe drill eah later of foam as I go up.

Thank you,
Bobster

[Dave V]

Dave,

Beautiful work.  How much foam is below the creek.

2".

Dave,

Are all your hills and valleys on a stacked foam base?  As I recall you built on a hollow core door.

Yes and yes.

I wish I would have paid better attention over the years.  I do not recall seeing pictures of the JD under construction only finished pictures.

This might help!

http://www.thevollmerfamily.com/Pennsy/Construction/index.html

[Bobster]

Dave,

Thank you very much.  That will be quite helpful.  I think it is going to take me awhile to digest all that information.  I like the idea of the T pins.   
I was thinking, after the base foam step, pinning  the track in place then putting down cork or foam in sections.

One last question for now.  How do you control dust  without layout damage?

Thank you for your time.
Happy New Year,
Bobster

[Dave V]

One last question for now.  How do you control dust  without layout damage?

Thank you for your time.
Happy New Year,
Bobster

I don't.