cork bed

For smaller layouts (around 2 x 4 feet or less), I'll start with a base made from two sheets of 1/2-inch thick Gatorfoam board laminated together. Subroadbed is either 1/2-inch Gatorfoam, 1/4-inch Gatorfoam, or 1/8-inch thick sheet styrene, depending on circumstances such as clearance over other track. The subroadbed is cut cookie-cutter style using a saber saw with a fine-tooth blade, and attached to the base with risers made from pieces of more foam. Roadbed is 1/8-inch thick by 1/2-inch wide double-sided foam adhesive tape.

For medium-sized layouts (around 2 x 8 feet or less), I'll start with a base made from two sheets of 2-inch thick extruded polystyrene foam insulation board laminated together with Liquid Nails for Foam, or LockTite Power Grab adhseive. Subroadbed is carved right into the foam using a hot wire tool and/or a packing knife; alternatively, I'll cut strips of insulation panel (similar to the Woodland Scenics products) with a saber saw, and glue it to the base. Roadbed is again 1/8-inch thick double-sided foam adhesive tape.

For large layouts, I'll start with a frame made of steel 2x4 structural members assembled with sheet metal screws. Onto the top of the steel frame I will bond a 2-inch thick extruded polystyrene foam insulation board using Liquid Nails for Foam, with 2-inch decking screws driven from below to secure the panels in place while the adhesive sets. Additional insulation panels are laminated on top as needed to gain the desired track elevation and scenery height. Subroadbed and roadbed same as above.

In addition to being dimenstionally stable regardless of environmental conditions--humidity, in particular--these construction materials result in strong yet exceptionally lightweight assemblies that are also easier to modify than layouts built from more traditional materials. The costs are reasonable as well.

Gatorfoam is available online from a variety of sources; some vendors will pre-cut the sheets for you, for a nominal fee. It's important to use Gatorfoam, as opposed to other cheaper foamcore products, as it won't warp when wet.

www.artgrafix.com/
www.dickblick.com/products/gatorfoam-board/
www.foamboardsource.com/

I purchase double-sided foam tape online as it's cheaper to get it in bulk, rather than the small rolls available in stores. While most any brand will do, I find 3M to have the most reliable adhesive.

www.tapecase.com/index.aspx

Styrene is available online in sheets much larger than you can get in stores. Minimum orders may apply, however.

www.professionalplastics.com/

Insulation panels, adhesives and structural steel members are all readily available at most home improvement stores, such as Lowe's or Home Depot. I avoid using any insulation boards other than extruded polystrene (the blue or pink stuff) because it's the most rigid and least messy to work with; expanded bead (white) panels are useless for anything except perhaps as scenery filler material.

Here are some photos of the construction of a smaller layout using Gatorfoam. This is the laminated base, on which I'm tracing the track plan:



Here I've attached the risers for the subroadbed:



And here's the subroadbed attached to the risers, with the double-sided foam tape roadbed applied:



I regret not having any construction photos of my past larger layouts. However, I do have an illustration showing the basic steel frame method:



I have one image showing how I've layered foam to build up massive (near floor to ceiling) scenery:



For what it's worth, my White River and Northern IV was built using the "medium-sized layout" techniques, and its successor, the WR&N V, was a vast room full of steel and foam, but never made it to the tracklaying stage. Although they were both N scale, all of the same construction methods are applicable for Z scale.

WR&N IV plan: whiteriverandnorthern.net/images/wrn4_large.gif
WR&N V plan: whiteriverandnorthern.net/images/wrn_5b.gif

Mr. Smith... THANK YOU for this most detailed posting! It is this type of valuable information and insight that really helps others... both novice and expert.

Now, if I could just have a small area for me to put this all into practice.

As for you losing your original effort in posting, I made a reply in another thread.

David,

Sorry that you had to write your post twice However, your photos, descriptions, and links to products is a great help to all of us Thank you!

David, amazing....extremely helpful....thank you!

Thanks David, very interesting certainly with the pics.

Am I right in thinking that this is more for "permanent" layouts compared to modules? I would be worried about transporting such foam board without them being framed by something hard/stronger.

Havoc wrote:

Am I right in thinking that this is more for "permanent" layouts compared to modules? I would be worried about transporting such foam board without them being framed by something hard/stronger.

Yes, my choice of materials is more appropriate for permanent home layouts or very small stand-alone portables (I built my own James River Branch to be a portable layout). I've found that a shell made from ordinary foamcore (not Gatorfoam, which can crack when struck) helps to protect a small portable from most damage. The foamcore gets dinged up, but not the layout. I cover the foamcore with self-adhesive vinyl shelving material for a nice finished look that also disguises the dings.

Modules, however, are indeed a different beast, as they tend to take more abuse than any other type of portable layout. Years ago I helped build some N-Trak modules that were solid extruded PS foam laminated with an outer shell of lauan plywood, plus reinforcements at the corners for legs. We found that most forms of damage can be avoided by having a module that weighs almost nothing by comparison to others!

That said, if the module owner is not present to ensure his/her work is protected, modules often suffer mysterious "accidents," so extra durability is desirable for modules that see a lot of mileage. Here's a construction series about some MiNi Mod-U-Trak modules that might be of interest. They're not solid foam, but they're still designed for extreme light weight and durability.

therailwire.net/forum/index.php/topic,17191.0.html

Thanks again for your toughts. It wouldn't be for modules that get aired at shows, but I have to make my layout modular so I can set it up in the appartment when I like. There is no place for a permanent setup. So it will get set up and teared down regulary.

Your point about light modules getting less hurt than others is however interesting. I'll keep that in mind.

Interesting thread as well. I really have to start constructing...

So....thanks for all the info again. I have lots of balsa and shellac (since David mentioned it...and I have so much), so I am going to do some tests and report here. To clarify, for what David calls subroadbed I am using foam pieces like Woodland Scenics but cut by myself, narrower for Z.

What myself I'm doing:

-All my track lies on a plywood subroadbed (about 3 millimeter thick)

-And for all mainlines, I put an IBL Z/Nn3 cork roadbed on the subroadbed.

The picture below shows the diverging double spur (upper part of the pic) that lies only on the subroadbed.



Dom

Dom,
Maybe you can answer this question or someone else can who may know.
I noticed in your picture the track over the bridge and you have a guard rail.

Would a railroad ever have a span of track over a short bridge, say about a 40-50' bridge without any guard rail since the span is so short?

I want my track work to look right, and when I did span a short stream I forgot about the guard rail. I can go back and add it if it is necessary?
Thanks,

tealplanes wrote:

Dom,
Maybe you can answer this question or someone else can who may know.
I noticed in your picture the track over the bridge and you have a guard rail.

Would a railroad ever have a span of track over a short bridge, say about a 40-50' bridge without any guard rail since the span is so short?

I want my track work to look right, and when I did span a short stream I forgot about the guard rail. I can go back and add it if it is necessary?
Thanks,

Bridge guard rails may be present on almost any bridge, although they would likely not be used for very short bridges, particularly those with a ballasted deck. Nowadays, they're not as prevalent as they used to be. So, depending on your modeling era, you may or may not need to add them.

the placement of the rails also varies--sometimes they are very close to the running rails, and sometimes they are further inboard. They are almost always of lighter rail.

Here are a few reference images:
www.johnweeks.com/bridges/rrpics/carver01.jpg
gallery.usgs.gov/images/05_01_2009/kOFr37Uhh0_05_01_2009/medium/RG0027.jpg
wapedia.mobi/thumb/333614618/en/fixed/470/470/PlateGirderBridgeUType.jpg
www.bikexprt.com/massfacil/boston/images/Bu%20bridge%20and%20underpass1.jpg

Dave,
Quite an open verdict based upon your pictures. One bridge doesn't have any rails and you would think it would while the third picture has rails that are so close to the center and such a short bridge I guess anything goes.

I will add some rail if I can talk someone into giving me about 6" of code 40 rail?

Any generous folks out there?
Loren

David K. Smith wrote:


Here are a few reference images:
www.johnweeks.com/bridges/rrpics/carver01.jpg
gallery.usgs.gov/images/05_01_2009/kOFr37Uhh0_05_01_2009/medium/RG0027.jpg
wapedia.mobi/thumb/333614618/en/fixed/470/470/PlateGirderBridgeUType.jpg
www.bikexprt.com/massfacil/boston/images/Bu%20bridge%20and%20underpass1.jpg [/quote]

Another question......why does the third picture depicting a short bridge have some sort of metal protective sides to it? Not really necessary are they? But definitely a nice detail to add.

I guess my era is modern as I am running diesels from the GPs to SDs.

tealplanes wrote:

David K. Smith wrote:

Here are a few reference images:
www.johnweeks.com/bridges/rrpics/carver01.jpg
gallery.usgs.gov/images/05_01_2009/kOFr37Uhh0_05_01_2009/medium/RG0027.jpg
wapedia.mobi/thumb/333614618/en/fixed/470/470/PlateGirderBridgeUType.jpg
www.bikexprt.com/massfacil/boston/images/Bu%20bridge%20and%20underpass1.jpg

Another question......why does the third picture depicting a short bridge have some sort of metal protective sides to it? Not really necessary are they? But definitely a nice detail to add.

I guess my era is modern as I am running diesels from the GPs to SDs.

That's a through plate girder bridge, and the tall parts are the girders. If you're referring to the lighter grey part along the right side only, I believe that's just a walkway, with a railing to the right. Or, if it's the slightly angled part along either side of the track you're referring to, those are individual gussets. The telephoto lens can mess up one's perception.

Sorry Loren, I only have an 8 1/2" piece and you wanted 6". Cheers, Jim CCRR:woohoo:

Thanks Dave,
I'll have to send you a close up photo of my two bridges and get your opinion on how to improve on their appearance and authenticity.
Much appreciated for your reply.
Loren

And as for you Mr smarty pants Jim O'Connell....all I can say is you better have bought Gayle a nice box of chocolates or some such gift for Valentine's.

Since I am a beggar for a scrap of code 40, I'll cheerfully accept your 8" of track.

Please put it in an over night express mail, insured, signature required, delivery confirmation tagged, and gift wrapped......but don't send it COD......I won't be home:P

Loren

Loren, Ok, but you owe me for the extra 2.5 inches! Cheers, Jim CCRR:woohoo:

Well, guys, sorry, I'm a lil' bit late and I discover that discussion about guardrails only now. Well, I guess Dave Smith gave us the fair reply. Myself I've not the least knowledge about the rule(s) that direct the existence of guardrails or not, on bridges. I preferred to add some because I find this aesthetically interresting, and because most of the girder bridges whom I saw pictures feature guardrails.

I wasn't really aware these have to be smaller and I used the same brand than my MTL track, code 55.... Maybe I should swap them with code 40.

Dom

Dom, Yes, these threads sometimes evolve into different topics. I like guard rails because I think they are cool looking. I send Loren some Code 40 yesterday. I think Code 40 is the way to go especially if you have Marklin steam as the bottoms of the engines tend to rub on the Code 55 rail I used back in the day. Beyond all this it is a good discussion and I'm sorry Charles, who posed the question, has never been back for an answer. Cheers, Jim CCRR:) Guard rail photo below