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elevation changes - questions regarding wedding cake construction

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feh
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elevation changes - questions regarding wedding cake construction
Posted by feh on Friday, November 27, 2009 10:17 AM

Hi folks!

My son and I are building a 4'x8' N-scale layout. The table has been constructed, and a layout design chosen. We've decided to use pink foam for construction. The base layer (0 height) is a 4'x8. sheet of foam.

I have 2 more sheets of foam ready to use for the different elevations of the layout. We are ready to lay track, and I'm not sure how to proceed. I can think of 2 options:

  1. use risers and skinny pieces of foam directly under the track to get all the track laid, and then worry about raising the surround terrain to the level of the track
  2. stack the foam and cut down into the foam to create the terrain  

Is there a preferred method? Are there any tutorials available to step me through the process?

One other question - during a section of track where the elevation is changing, how do you create a smooth transition?

Thanks!

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Posted by selector on Friday, November 27, 2009 1:05 PM

I am glad you got to your last question, 'cuz I'm going to address it first. Big Smile

It is hard to do in foam.  About the best way, if you can still do it, is to draw the ideal vertical curves and the middle consistent graded portions with markers on the sides of a ramp, something that would have a rock face, retaining wall, or more dirt and carved terrain foam outboard of it once the grade is shaped...if you follow.  What I mean is, you need to draw yourself a visible template using a sharp black marker.

Then, using what works for you (I use a carving knife initially, than resort to a bit of wire brushing...messy!...followed by sanding block) you use the drawn line to cut away what lies above it for the width of your sub-roadbed/right of way.  Ideally, you can lay foam roadbed, if you wish, or just fix the track to what is not carved and sanded away.

Or, rough it out and then slap and spread plaster or spackle, or a putty...anything that can be spread, that will stay put when you leave it, and that you can shape to form those all-important vertical curves into and out of your elevation levels.

I don't want to come across as a lecturer/I told-you-so type, but this probably should have been figured out before this point so that you had a defined approach to the requirement.  Many of us would resort to 1.4" or slightly thicker sub-roadbed made of plywood or MDF, something that could be screwed tight and flush with the previous lower level, and then bent up into a nice transition with one or more risers below it for support.  Then a forced bend back to level at the top of the grade.

As for the skinny pieces of foam....been there, and I was never entirely happy with the results.   That was me, and my limitations.  You may have a better handle on how to effect it.  What you could do is rough it out with the slivers of foam, and then apply that smoothed overcoat of some slatherable substance to get your grade with vertical curves.  I was about to try that approach when I learned it was moot on my last layout.  I had to destroy it for a basement reno.

Stacking the foam is necessary for relief in terrain, but you should pause and consider how it is to look when you are done...it's final when you remove material from foam, unless you are willing to double your work and glue more foam into place.  Once you begin to carve your vision, go slow, pause, do some more, and be patient.  Don't settle for good enough because you will have to go back and improve it.

At any time of carving and shaping foam, always bear in mind its utility.  What is the purpose for a notch here, an abrupt drop there?  What effect will my work have on the way the trains running past/near here have on those trains.  Have I left enough clearances, particularly when I intend to add plaster cast rocks to those surfaces, or maybe some trees along the slope?

I hope that helps a bit.  I am glad to see you pausing here, regrouping, and hopefully you are willing to even undo some of what you have done in order to gain a better footfhold on this project.  It will be worth it.

-Crandell

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Posted by Doc in CT on Friday, November 27, 2009 1:06 PM

You should search the message threads here for "foam" or "foam construction".

That said, I think you should be thinking of build up layers then cut and form the terrain from the layers.  As my planned layout is foam based, I have looked into Woodland Scenics foam inclines [link] for creating grades.  Not terribly expensive.

If the layout was open grid or cookie cutter, the plywood deck or roadbed on risers could be used to create the inclines needed.  I think trying to duplicate that techique with foam board would be harder, but not impossible.

Foam board is more a replacement for thin shell or other terrain construction techniques, especially for layouts that are moved a lot.

 Alan

Co-owner of the proposed CT River Valley RR (HO scale) http://home.comcast.net/~docinct/CTRiverValleyRR/

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Posted by BATMAN on Friday, November 27, 2009 1:14 PM

Have you looked into using spline as your roadbed? It makes a very nice natural transition into and out of a grade change. In this photo you can see where my spline roadbed butts up to my 2" foam. I have put the foam directly onto 1"x 4" open grid construction. The splines are attached to the same open grid and then the foam fitted around the supports. I will build the foam up around the splines for terrain when the time comes. Do a search on spline roadbed, both on the forum and Google. You will learn a lot about it, and if you so choose, build it to suit your own needs. On the foam I put down cork roadbed using latex caulk. On the splines you can attach the track right to the spline.  I only used splines for the ups and downs and I'm delighted with the results.

Disregard the plywood you see as that is only spot I have used it. It is for something that is unique to my layout. You can put foam right on the open grid without plywood.

You could, I suppose, stack your foam and carve it out. Using a rasp I find it easy to carve out foam. In the last photo I carved out the foam to lower the cork roadbed, to bring the track level down to the foam for my sidings.  I think most people grind down the cork to achieve this ,but I found lowering the cork into the foam was a much quicker and smoother way to do it. Just myMy 2 cents

 

 

 

 

 

 

 

                                                                Brent

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by markpierce on Friday, November 27, 2009 4:34 PM

The continuous stream of threads like this confirms my decision to stick with plywood "cookie cutter" and cardboard-strip-reinforced-plaster-cloth-land-form construction, although small dioramas can warrant foam-sheet construction.  Perhaps it is just a Woodland Scenics plot to sell foam, and the apparent lack/fear of basic carpentry skills.

Mark

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Posted by wjstix on Friday, November 27, 2009 5:30 PM

I would look into Woodland Scenics foam risers, which have grades that come in 2-3-4% elevations. AFAIK they're only available in the ones designed for HO, but they will work OK in N scale too. I'd go with 2% as your maximum grade.  

Stix
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Posted by JSperan on Friday, November 27, 2009 5:34 PM

markpierce
The continuous stream of threads like this confirms my decision to stick with plywood "cookie cutter" and cardboard-strip-reinforced-plaster-cloth-land-form construction

 

I tend to think that spline roadbed, or even the "cookie cutter" style are less trouble than trying to manage changes in elevation with foam.

The cardboard lattice supported hardshell works well for me.

feh
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Posted by feh on Friday, November 27, 2009 7:01 PM

 I should let folks know that the reason we went w/ a 4x8 table and foam is that I need this layout to be portable. We're building it in my son's bedroom (he has a large bedroom), and eventually I'll want to be able to remove it from his room without destroying it.

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Posted by cowman on Friday, November 27, 2009 10:08 PM

Usually the only full sheet(s) of foam used are for the base layer.  To add rising terrain, chunks (leftovers from a construction site) are attached in layers (need not be a solid), until the desired height is reached.  You cut into it for below track level scenery.  If you plan to  have siginificant drops below track level, chunks can be glued underneath.  For distant rising terrain, you are not limited to foam, you can use a hardshell method as long as you don't plan to plant trees in it.

There are a number of articles as well as threads on the forums on using foam.  For articles go to the top of this page click on RESOURCES, then Index of Magazines, do a search for foam.  It has articles from many mags not just MR.

Good luck,

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Posted by rrebell on Friday, November 27, 2009 11:17 PM

Build your 1x4 frame work and top it with 2" foam, you don't need ply and if you want to screw something to it you can use small pieces of ply caulked in place to screw to (that's how I mount my ground throws). Use WS incline starters and free white or other foam. Carve your basic landforms and the plaster cloth will do the rest. I can lift my layout with one finger ( 2x4 module).

feh
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Posted by feh on Saturday, November 28, 2009 8:33 AM

 To paraphrase, I can use foam and risers/inclines to get the track laid, and then make the surrounding terrain smooth with plaster cloth, or some other method? It would make things much easier if I knew I could get a rough shape w/ foam and then smooth things out later w/ some other product.

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Posted by Doc in CT on Saturday, November 28, 2009 8:51 AM

feh
 To paraphrase, I can use foam and risers/inclines to get the track laid, and then make the surrounding terrain smooth with plaster cloth, or some other method?

 

I believe the answer is 'yes'.
See the "Step by Step" article on pages 32-34 by Neil Besougloff in the Jan 2010 issue of MR.

Alan

Co-owner of the proposed CT River Valley RR (HO scale) http://home.comcast.net/~docinct/CTRiverValleyRR/

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Posted by rrebell on Saturday, November 28, 2009 10:59 AM

Definitely yes, and if you need a cheap place to get plaster cloth go to ASW or Bicks, $1.50 a roll or less.

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Posted by selector on Saturday, November 28, 2009 11:04 AM

The key is to not have dips and bumps that cause your engine to lose traction on the climbs.  It won't be a problem on descents, but when trailing cars on a grade in the climb, steamers may have a tough time of it.  So, try to keep the rail tops at 'grade' all the way up the grade, and that means a good subsurface and good support under the ties...no sagging, try not to have twists that make the engines pitch and roll.

-Crandell

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Posted by fwright on Saturday, November 28, 2009 11:52 AM

 

feh

 To paraphrase, I can use foam and risers/inclines to get the track laid, and then make the surrounding terrain smooth with plaster cloth, or some other method? It would make things much easier if I knew I could get a rough shape w/ foam and then smooth things out later w/ some other product.

The 4x6 portable test layout I am currently building has similar construction.  I have 1x6 rails around the outside with 1/4" ply with 2" foam on top inside the frame.  Having always build traditional cookie cutter plywood layouts or flat foam layouts in the past, this will be my first experiment with grades on foam.

I am using Homasote on top of the foam for roadbed, and will eventually have some to all of the track hand laid.  For that reason, WS risers and inclines are out.  I will be attempting to use the cookie cutter technique with the ply/foam/Homasote sandwich - I may need to go to thinner foam to make it work, as the 2" foam plus 1/4" ply may be too stiff to bend suitably on such a small layout.

Another alternative to be considered is build my own slopes with additional foam stacks and then put the Homasote roadbed on top.  The Homasote's limited rigidity will likely allow less than perfectly smooth foam slopes (thank goodness).

The good point is that the layout is light and portable as planned.  The downside is that the track plan calls for an elevated track over top of a hidden siding.  Doable with traditional plywood cookie cutter by allowing a little extra rise for the track support thickness; with 2" thick foam the concept doesn't work.  I'll have to solve this one later.

Unfortunately, the grades won't be for a while - I'll be using the layout as a test track for my locomotive building efforts in the beginning.  So I can't tell you which system of grades works or doesn't work, yet.  I plan on posting pictures next weekend of the current status, I'll provide a link then.

Fred W

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Posted by dgwinup on Sunday, November 29, 2009 8:30 PM

feh

Hi folks!

My son and I are building a 4'x8' N-scale layout. The table has been constructed, and a layout design chosen. We've decided to use pink foam for construction. The base layer (0 height) is a 4'x8. sheet of foam.

I have 2 more sheets of foam ready to use for the different elevations of the layout. We are ready to lay track, and I'm not sure how to proceed. I can think of 2 options:

  1. use risers and skinny pieces of foam directly under the track to get all the track laid, and then worry about raising the surround terrain to the level of the track
  2. stack the foam and cut down into the foam to create the terrain  

Is there a preferred method? Are there any tutorials available to step me through the process?

One other question - during a section of track where the elevation is changing, how do you create a smooth transition?

Thanks!

I had no problem making elevation changes using nothing but foam.

Here is a photo of the beginning of construction of the addition to my layout.  The addition is 30"x 48", the same size as the original layout.

The picture shows how I used small blocks of foam to determine the elevations of the tracks at various points around the layout.  These blocks were for measuring purposes only and were not used to actually make the elevation changes.  Look carefully at the bottom level of foam and you will see some black lines.  The lines were used to cut the bottom level of foam, which then became the TOP level on the layout.  I used 1" foam for all of this.

The next picture shows an intermediate step in the construction process.

Here you can see how pieces of 1" foam were stacked to gain elevation and form a continuous grade without dips or bumps.  This method automatically made smooth transitions into the inclines.  The turnout in the lower middle of the picture is at 0" elevation.  The track that crosses over it is at 2" elevation.  By the time that track circles around the back and over to the left side of the layout, it reaches 4" of elevation.

This is one of the 'money' pictures.  How to get a smooth transition into a rising grade:

The top level of foam is supported by small blocks of foam of increasing height.  This raises the top foam sheet while keeping the grade even from one end to the next.

I considered using WS foam risers and inclines but rejected them for two reasons: cost and pre-set gradients.  Their smallest gradient is 2" and I didn't want my grade that steep.  My finished grade is about 1.5%

There is another method of achieving a smooth incline, but it takes more effort.  On my original layout, I carved foam blocks to make inclines.  I made a cardboard template of the shape I needed, then flipped the template over and used it to cut a block to that shape.  Then I carved the BOTTOM of the block to make the incline.  Flipping the template and cutting the block left the TOP of the block perfectly smooth.  Any inconsistancies in my carving is buried at the bottom of the block.  In this next photo, the inner radius track is elevated above the surrounding terrain.  The elevated part was done as just described, reversed cutting of the block with the rough carving on the bottom.

In other areas of the layout, I did carve the top of the block but this can result in dips or bumps.  With this method, I cut a square block to length, carefully cut the incline along the sides of the block, then trimmed the sides of the piece to fit where it needed to go.  The next photo shows how the inclines fit.  There are two tracks in the tunnel.  Both are on inclines but the inclines are opposite to one another (one rises while the other descends).

I used the same method in another area.  Later on, I discovered that my carving had created a dip in the trackwork which caused stalling or limited the length of trains that could climb the hill.  To correct this error, I made slits in the underlying foam below the dip and inserted trimmed pieces of cork into the slit.  This brought the track up to level.  I used cork in the slits rather than foam because the pressure of the slit foam just crushed tiny pieces of foam.  The cork didn't compress.  Here is a photo of the corrected dip:

All of this resulted in smooth elevation changes except for the dip error which was easily corrected.  Remember, this is all built out of foam.  No trees were harmed in the construction of this layout!  LOL

Hope this helps you decide.  Using foam sure makes layout construction a lot easier.  You do have to think outside the box sometimes because foam construction IS different from standard wood construction methods.

Darrell, quiet...for now

Darrell, quiet...for now
feh
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Posted by feh on Sunday, December 6, 2009 7:42 AM

 Fabulous information and pix! I will follow your example.

 Thanks very much!

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