Best material for HO layout road bed

Started by pacchardon, May 18, 2011, 01:39:07 PM

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I am working on my first model train layout. I was planning on putting down 1/2 inch styrofoam insulation sheets on top of the plywood. However, I just got a package of Atlas track nails and see that they are only 1/2 inch long. They will never get down to the plywood. Will they anchor the track well enough in the stryofoam? I would think that they wouldn't. I didn't want to get into the cork road bed. Any suggestions, please?


I'm missing your question here.   You ask for best roadbed material then say you don't want to get into cork.

Now the best "roadbed" IMO is Homasote which can be bought already cut for your roadbed.   But I suspect you may be asking how to actually fasten the track down.   Do not use nails for track OR roadbed.   Use an adhesive caulk, available at your local big box store.   Get the cheapest stuff which works fine.   A small amount under the track is sufficient.

Once your track or roadbed is caulked down, add some weight until it sets.   An advantage is that it can be easily removed so track can be repositioned.

Dave Mason

D&G RR (Dunstead & Granford) in On30
"In matters of style, swim with the current;
in matters of principle, stand like a rock."   Thos. Jefferson

The 2nd Amendment, America's 1st Homeland Security


I was talking about not wanting to get into the cork strip, width a little wider than the track. I was asking about a substitute for the 1/2 inch styrofoam insulation over the plywood. In other words, what do I want to put between the plywood and the track.


So I guess then the answer would be Homasote. Never heard of it. So I guess I will have to track it down
Thanks, Paul


If you don't put anything between the track and plywood it will make a lot of noise running. Most use the cork. If you can find some on the cheap you can also use strips of indoor/outdoor carpet. I got some once for nothing and it worked well.


Jerrys HO

if you are using ez track it does not have to have a roadbed as it is made to the track. I used 1/2 '' styrofoam and tacked that to my plywood then glued my track to the foam. works great and you can dig into the foam to make ponds and stuff.



Think of the surface which constitutes most of your layout as ground level. You can build up from there (hills and mountains) or down (ditches, a little stream, a culvert or whatever). Styrofoam is good for this level because it is light and easy to work with. Also, you are not limited to one-inch foam.

That said, I think you're asking what to use for your roadbed and subroadbed. Here you have beaucoup options. If your layout is mostly flat you can just use the Styrofoam for your subroadbed and put roadbed right on top of it. If you are planning a mountainous layout you might want to build your subroadbed out of bendable wooden splines bent and glued into the needed shapes, plywood strips or cookie cutter style in which you cut all of your track alignments from a piece of plywood and use blocks to raise the various sections to the proper elevation. (Be sure that the places where grades begin are done as gradually and smoothly as possible to reduce operational problems. You'll also want to support your subroadbed frequently so you don't have dips here and there. The same goes for curves in level track.) You can also do the cookie style subroadbed when you use an open framework. That becomes something very similar looking to the all-from-one-piece subroadbed only (maybe) a little easier to work on. Whichever way you choose to do your subroadbed, you'll still need roadbed on top, unless you are modeling a nearly broke railroad or a switching/industrial/yard set up in which case you might want to forget much in the way of roadbed because many such tracks are laid on or have become nearly flush with ground level.

You also have many choices for your roadbed. Some track, like Bachmann EZ Track, comes with attached roadbed which you can mount directly to your subroadbed. Other manufacturers offer similar products. You can use Homasote as suggested above. This a time-honored way to build a layout but I have serious misgivings about it. Homasote expands and contracts quite a bit as seasonal humidy levels change. That can make for major problems with your track because the metal rails and plastic ties move very little. Cork is much more dimensionally stable, inexpensive and easy to use. I suggest that you give cork some serious consideration. There is a similar plastic product (expanded vinyl, I think) but I've never used it. I have used expanded vinyl wallpaper and found it to be exceedingly easy-to-use, attractive and durable. What does that say about expanded vinyl roadbed? I don't know. But it does at least suggest good things. There's also a roll out sticky roadbed. It's relatively thin so it won't look like high iron but it will hold itself and your track in place. You can get away without ballasting (the rock, cinders, etc. which holds the track in place on 12 inches to the foot railroads) some model railroad tracks, like cork or the ones which already have plastic ballast or something just for children who won't care as long as the trains go at light speed. However, you MUST ballast the sticky stuff because anything else which touches it will stick to it and that will lead to a cruddy looking railroad. The other ways of doing roadbed (plastic, cork, homasote) should be ballasted for appearance. Yes, that applies to the roadbed attached trackage, too.

You also have to make a few decisions about your track itself, or at least the rails. Specifically, you need to decide about material, size, type and minimum curvature. Track comes in steel, brass and nickel-silver. Steel looks great but it is problematic unless you live in the desert where there isn't enough moisture in the air to rust it. However, that particular theory doesn't always stand up. Let's face it, steel rusts. Brass was the gold standard at one time but it also rusts. Only we call it oxidation or tarnish. Whatever the name, it creates serious electrical conductivity problems and always seems to demand a cleaning. This is rarely somebody's favorite thing to do when they have some time to spend with their model railroad. That leaves nickel-silver, which is a lie because there isn't any silver in it. It's not as good a conductor as brass, or even steel, but it oxidizes much more slowly and the oxidation impedes the flow of electricity from the rails to the trains less than steel or brass. Larger gauge models use aluminum but that's not a viable option in HO. The less efficient conduction of N-S is its problem but it is an easily solved one. Just use a good power buss under the layout and run frequent feeders up to the rails.

By size, we are talking about what you may have seen advertised as Code something. That just means the height of the rail in one-thousandths of an inch. Code 100 is 100/1000 of an inch, or .1 inch. Code 70 is 70/1000, and so on. There is a good selection of rail in Codes 100, 83 and 70. You can also use Code 55 for HO but you'll end up handlaying much of your track because you won't find it already assembled for you. Just about everybody used Code 100 brass at one time, but Code 83 and even 70 is seen more and more today. Those somewhat smaller sizes just look more in scale. An important consideration in picking rail height is whether you can find things such as turnouts (often called switches) and crossings (two intersecting tracks) in the size and material you want. Be aware that it is possible to connect different sizes of rail together so you are not absolutely limited to using just one size. Indeed, 12":1' railroads typically used smaller rail on sidings and spurs which carried less weight and had trains moving slowly. You can imitate this by using lower roadbed and smaller rail on sidings and spurs. The difference between Codes 100 and 83 or Codes 83 and 70 might not sound very significant, but you will see the difference.

Type refers to the format of the track you buy. It can be sectional (this is what you'll see most often and it comes in train sets), flexible or completely disassembled. Making your track from rough roadbed, individual wooden ties (or plastic or PC board) is called scratch building or handlaying. It looks super and you can make any shape you want but it is time consuming and a huge amount of work. This is an impediment for new hobbyists who want to get the trains rolling. It's also a lot more difficult than sectional or flex track. Sectional track works quite well as long as it's on a firm base. It tends not to want to stay together on its own; sectional track with attached plastic roadbed is an exception here. It goes down quickly and it's reliable, but it can get expensive. That leaves flex track (comes in 36" lengths) with prefab turnouts and crossings. This is probably the best choice for most newbies as it gets trains running quickly and is foolproof if you use just a little care in putting it down. You'll find virtually any track components (turnouts, etc.) you need to complete your railroad.

Minimum curvature refers to how broad or tight your curves are. There are at least two considerations here: What will fit and what kinds of equipment will you use. If you are limited to a 4'x8' plywood slab, you will be limited to 22" radius curves. Since what comes in train sets is almost always 18"R, 22" might sound pretty good. It isn't. Eighteen inch radius curves are very tight. They will accommodate only smaller equipment like four-axle diesels, small steamers (0-4-0, 0-6-0, 4-4-0, and maybe a 2-6-0 or a 4-6-0), short freight cars (no more than 40' is best, maybe a few 50' or 55' cars will make it) and "shorty" passenger cars. This means old-style cars which were around 40-45' long. You might get away with running 60' passenger cars if you have extra long coupler shanks, but they won't look very great. This is less of a consideration if you're building a railroad for children who are a little less concerned with authenticity or overall appearance.

With 22" curves, you can use rolling stock up to 60'. You might even get some longer passengers cars around such curves, but you'll have the appearance problem again. Six-axle diesels should be okay on 22" radius. Somewhat larger steam engines will probably work, like Prairies (2-6-2), Consolidations (2-8-0) and even some Mikados (2-8-2), but you shouldn't plan on getting really big locomotives around such curves. Many of Bachmann's larger steam locos will clear fairly tight curves, but you won't really know unless you try them out. If you want truly big steam, like Northerns and Articulateds, you should be thinking in the range of 24" to 36" radii, recognizing again that, while some locos might make it around, they might not do so consistently or at anything faster than a crawl.

Well, this dissertation has gotten way too long, but I hope you find the information useful. Welcome to the hobby.
                                                                                                                                                                  -- D


That's a lot to absorb. It is going to take a while. Some of the stuff youre talking about has already been decided. I am going with HO code 83 nickel-silver on 5 x 8 benchwork. The first part of the layout is going to be a figure 8 with 18R track within a larger 22R track loop with two turnouts to take it into Part 2 of the layout which will be a 4x8 layout perpendicular to Part 1. Using steel work bench legs with a stringer and 2x4's bolted to the legs at the top  (I want to be able to land a plane on this sucker) with the plywood screwed to the 2x4's. So the big question now is what goes on top of the plywood? This I will have to mull after reading all this again. Thanks for the info, Paul

Jim Banner

You don't want cork and I would recommend NOT using Homasote due to its propensity to warp and swell when wet (think track ballasting.)  By all means use 1/2" styrofoam.  Glue it to your plywood with white glue or construction adhesive.  Wait until the glue dries.  Then glue the track to the foam with white glue and either pin it in place or weight it with bricks until the glue dries.  Any white glue will work between the styrofoam and the plywood but Weldbond is the best choice between the track and the styrofoam due to its excellent adhesion to the plastic ties.

If you use a construction adhesive, be sure it is rated for use with styrofoam.  My personal preference is PL Premium, sold in calking cartridges.  Do NOT use waterproof glue under the track unless you are absolutely sure you will never want to remove the track.  With Weldbond, all you need to do is wet it with warm water, wait five minutes, and gently lift the track with a putty knife.

Growing older is mandatory but growing up is optional.


Donaldon wrote a textbook, but it's a good one!  Here's a little more ... footnotes, perhaps?

Many layouts are built with a framework (called "benchwork") covered by a thicker (say 2") layer of styrofoam building board. You design your track layout FIRST, then build the benchwork with solid wood directly below where the track will be. Then, on top of the thick styrofoam, you lay track with one of the several roadbeds: EZtrack with built-in roadbed, or Atlas (etc.) track with pre-formed homasote, ground corr or foam trapazoidal-profile roadbed. The principle is that you want a solid support under the train and rails, so they don't sway or twist. But you want to save on weight and materials and (as you will read below) have access for electrical wiring from below the layout. On the other hand, you want your layout to look as realistically like a real railroad in a real countryside or town, as you can make it. Study the real world itself, like an artist, and then see how other model railroaders have solved various problems of duplicating reality in miniature. Finally, be creative
on your own, try new things, and expand on the ideas that turn out to look good.
By the way, where you are building a switchyard, you'll find the full-scale real-world railroads have NO roadbed. The whole yard is a roadbed, in effect.

It helps, of course, to understand why these various things are done on the prototype roads. Roadbed is gravel that will hold the ties in place so they don't shift, and also drain off rainwater so the ties don't rot (creosote helps, but drainage is still important). In a railyard, it's virtually all gravel all over. Ties are square timbers, not the flat pieces you see on most model track. You put that down on top of a "roadbed" and fill in around it with a little sand, so it LOOKS like the top of a big square cross-tie buried in the little mound that is the roadbed.

You, of course, attach the tie with liquid nails or maybe metal ones (there are schools of though on this, concerned with whether you want to pull it up and reposition it next year or not). That's part of creating the illusion but being practical. One more reason for the solid foundation under the track is to cut down noise and rattle. Homasote is simply very dense pressed paper; it will absorb sound energy, but transmit it down to whatever is below it. It does have some disadvantages; like most things in this hobby, there are those who swear by it and those who think it's the worst crap in the world. That's what makes life interesting -- they are both right, according to their own standards. Styrofoam is light and foamy, so it swallows up the sound energy. The goal is to keep that train rumble from resonating in the frame of the benchwork. That's where you get a noisy train room. Well, yes, a lot of the noise goes into the air: sound-absorbing walls and ceiling help, too. And a carpet or rubber mat on the floor is a very good idea!

Why use that more expensive (but not that much more) 2" styrofoam? For one thing, you can dig ditches, arroyos, creeks, and what-have-you easily and naturally. You can add hills by gluing down a chunk and then sculpturing it. And you can do this afterwards, if you are still finding your way. Styrofoam take most glues (some will eat it up, to test on a scrap first) and water-based paints and scenic pastes. Be careful, though, with spray paints like Krylon. Most of these will also eat styrofoam. Test on a scrap.

Flowing hills are part of making scenery natural. Except for railyards, airport runways and football fields, most ground has undulations of some sort. You can create this on a thick styrofoam base with a rasp or even a wire brush, then sand and scenic (if you are new to the hobby, "to scenic" is a verb used only in this hobby that means "to put scenery on the layout so it looks realistic like the real world").

Another advantage of having thick styrofoam without a solid layer of [ply]wood under the whole thing is that you can put wires through to light buildings and power train rails, just by poking a skewer or even a piece of coat-hanger wire, through the stuff. Just go at an angle under the track so you miss the reinforcing piece directly below.

Yes, I said power train rails. DON'T rely on rails and rail-joiners to conduct the juice from one feed point, unless it's a very small layout (a single loop, say). Use heavy copper wire (building wire, 16 gauge or heavier if it's a big pike) under the layout. Every ten feet or so (there are many opinions about the proper distance, and you will form your own soon enough), run a smaller wire up to each side of the track from that main buss wire to the correct rail or the track itself. Use the insulation color as a code to guide you (as any electrician would do!) so you don't cause a short circuit and blow out your power supply. Always solder the wires and insulate with electrician's tape. There's a trick to soldering the wire to the rails: using the lightest touch and the minimum amount of solder, gently tack it to the "back" side where you don't see it from the front of the layout, and don't make a bump that will derail a wheel. You may have to file down some solder when you're done (no, don't wrap THIS joint with tape!).

It's all part of making your layout LOOK realistic, but work well with the systems (i.e., electricity on rails instead of real steam or diesel -powered locos) we have to use at 1/87 of the real world to create the illusion of reality in miniature.

Happy rails to you!




Thank you for the kind words, and may I add a few to your clear suggestions.


A heavy gauge power buss (actually two wires) of at least 16 ga. wire is best. Stranded wire costs more but it's easier to work with. It has greater ampacity than solid wire, too, so you can use one size smaller. Sixteen gauge stranded, the size of most regular duty extension cords is OK; 14 ga. is better and necessary with solid wire and larger pikes. You can speed up attaching feeders if you use Scotchloch (suitcase) connectors but they're a little pricey. Insulate soldered wires with shrink tubing or liquid electrical tape. Regular electrical tape can dry out and let go, especially with the very small wires we use for most things. Keep your feeders to no more than 12". Some folks will even say 8" or 6" but those lengths get very hard to respect unless your power busses run right under your track. By the way, loosely twist your power buss wires to prevent interference with DCC signals if you have long runs.

You only need a very short length of wire, like 1/8", soldered against your rails. Put it on the outside of your rails so it can't interfere with wheel flanges. If you must put it between the rails, do so very carefully or solder to the bottoms of the rails. I find it easiest to clean both the end of my wire and the attachment point on the rail, apply a very tiny bit of flux to each, heat them enough to get a tiny bit of solder on each, and then finish the connection by applying heat to the top of the rail while holding the feeder against the rail until the solder turns shiny (melts). Hold the connection just another few seconds and you're finished. Your solder joint should be shiny; redo if i's not. This technique is fast so it won't melt your ties and roadbed. I use a very small wire brush to clean my attachment point on the rail and flux in a little marker like deal which lets me put it exactly where I want it. ALWAYS use non-acid core solder and acid-free flux. You want this to  last, not slowly corrode into a giant resistor.

Well, I guess railsider and I have worked these topics to death. Now it's time for you to get busy. Good luck, although you won't need it if you're just a bit careful.

                                                                                -- D


Well, I may be in the minority here, but many modelers on the other forums and in general have had no problem with the Homasote.
Unless your layout is in the pool, or outside, or in a leaky basement, you won't have a problem with the stuff.
Check it out here:

As for the styrofoam, some have complained that it seems to echo the noise from the train, but I have no experience in that.   I've always used the Homasote.
Good luck.
Dave Mason

D&G RR (Dunstead & Granford) in On30
"In matters of style, swim with the current;
in matters of principle, stand like a rock."   Thos. Jefferson

The 2nd Amendment, America's 1st Homeland Security



I don't think anyone feels that Homasote is a bad product. On the contrary, it's an excellent product. How else could it have stayed in the marketplace for so long? It's just that raw Homasote does react with humidity to a degree that is problematic for model railroads. Sure, you can paint it or seal it all around and it will be fine. Unsealed Homasote will also be fine in places with consistent humidy, like the desert or maybe an attic. But the sealing and extra care which Homasote requires in most places is incompatible with the interests of new model rails who want to get the trains moving now.

It's the same with handlaying track. No one can dispute that handlaid track allows for infinite alignment possibilities or that it looks super. But would we suggest to a new MR that his track should be handlaid? I don't think so because we know that the newbie wants to see those trains moving soon, not after weeks of laying track (which the newbie doesn't understand all that well in the first place).

So. Nothing personal and no criticism of folks who use Homasote or handlay track. But it's not for beginners.
                                                                                                                                                                  -- D


I am strongly considering Homasote. Sealing it sounds like the way to go. I guess without further input I would probably go with a polyurethane varnish. Can anybody suggest anything else?

Also, if by 'handlaying' track you are talking about laying the individual pieces of track and attaching them to the road bed one at a time, that was what I was planning to do. I didn't know there was any other option. Unless you are talking about the 'easy track' products that have an attached roadbed simulating ballast. I don't like the looks of that stuff.

I have told my son that part 1 of this layout is a project for this summer. It isn't going to happen over night. We are going to take our time and do it right. He is 13 in a week and I told him if he gets into this we could be working on it thru his teens. He seems to be ok with that.

CNE Runner

In our part of the country (the Heart of Dixie...or heaven for short) Homasote is almost impossible to obtain. What is available is Johns Mansville 'black board'. This is a very similar product to Homasote and is used as underlayment for exterior walls. I have constructed several layouts (for myself and others) using this product and have had no adverse results. One side of the 'black board' and printed with the JM logo. Turn this side down and secure your track/roadbed to the reverse side. 'Black board' holds spikes quite well, allows for a good adhesive hold, and provides an excellent 'underlayment' for scenery - due to its rough surface. About the only drawbacks are: 1) it is a bit heavier than Styrofoam, and 2) the edges need protection from 'fraying'...a fascia board will suffice.

Check your local home improvement store for this product and see what you think.

"Keeping my hand on the throttle...and my eyes on the rail"