Hi everyone. This is my 1st post in the MR forums. While not new to model railroading I have been messing around with layouts, small ones for a long time.I finally started in a room sized layout in my bedroom. I have half the benchwork up on one side. My question is what is sub roadbed and will I need it for my benchwork which is plywood on beams narrow and wide sections. I plan to model in N scale just a point to point with a small intermodal yard. I will be using homostote roadbed. Also is there a good way to get rid of pencil lines in the plywood? I made allot of changes from the 1st drawings. Thanks.
The plywood is your sub roadbed, or at least it could be. Make it smooth and put your cork or other roadbed directly on top of that. For yards you will want a smooth sheet of Homasote or similar material, lay the tracks directly on that. An inter-modal yard would almost have the rails below the level of the truck aprons so that other equipment can move about freely. For a first layout, I would cut cardboard or styrene to fit in between the rails and on either side of the tracks.Here is a picture of how my repair yard was built, the idea would work for your inter-modal yard. I used corrugated cardboard which has caused problems with weather shifts, you will need to use a more stable product to do something similar, and even then be prepared to make adjustments.
You use the sub roadbed for strength and stability, and you use the roadbed for looks, a smooth surface and a softer surface that will take tacks easily but will not let them loosen up in use.
The LION does not use the sub-roadbed at all, him puts the fiber board (Homasote, Celotex etc) directly on the table frame. But then him is cheap, is prone to make changes, and does not use roadbed anyway since him models subway trains that run in concrete holes in the ground.
ROAR
Don’t worry about the pencil lines. They will eventually get covered up with scenery.
Welcome to the forums.
Be sure to seal your plywood top and bottom. This will reduce the problems caused by changes in the weather, humidity and dryness causing the plywood to shrink and swell, thus upseting your trackwork.
As for the pencil lines, if you need to get them out of the way so that you follow the right ones, buy or make a small sanding block. You could use a power sander, as long as you are careful not to erase the lines you need to keep. If you are thinking they will show through your paint and scenery materials, the sealant, earth tone paint and scenery materials should cover them with no problems.
Good luck,
Richard
Thanks for the tips, so basically the top of the plywood is the subroadbed then. The pencil marks were from when I was trying out different things but I wanted to erase them for the final plan. What is a good sealer?
Hi, and welcome to the forum - and the Hobby!
I’ve been playing with trains since the mid-50s, and have built two 11x15 double layer HO layouts in the last 15 years. The benchwork is plywood, and I use cork roadbed - the combination I’ve used since the 1960s.
One thing I’ve added on these two latest layouts is applying thin sheet cork over the benchwork wherever there is NO track/roadbed. This - in my opinion - gives a nice surface to lay out structures and roads and such, and it covers over the seams and uneveness in the plywood.
Obviously everyone has their own preferences, and cork ain’t cheap, but this has worked nicely for me.
[#welcome] Welcome aboard!
As has been said, with the construction method you described your plywood layer is your sub-roadbed - the last thing before the air that represents the solid earth under a real railroad.
In my case my subgrade (same thing, slightly different name) is also plywood, cut to right-of-way shape (aka cookie-cut) with the parts that won’t support track or lineside buildings removed. I’m modeling a stretch of countryside that resembles the depths of the Grand Canyon or the more rugged parts of West Virginia - cut out five acres, lay it flat, iron it and sell it as ten acres. Flat plywood would simply be in the way where most track is on grades and the landforms are vertical.
Sounds as if you have a workable plan. Homasote is good for holding spikes, but should be sealed if you might run into humidity changes. I anchor my track with latex caulk, so I can get away with sculpted extruded foam (fan-fold underlayment) for roadbed.
Sly and cunning trick. Get wheels rolling as soon as possible - even if it’s just a switcher with two gondolas loaded with rail joiners and track nails on your first length of flex (powered with clip-on leads.) Playing with it might slow construction, but the urge to make its playground bigger will keep construction moving.
Again, [#welcome]
Chuck (Modeling Central Japan in September, 1964)
I’d only bother with erasing the pencil lines if you might get confused or misguided about where to put track etc. It can help to “clear away” the false starts sometimes and I keep a Pink Pearl eraser handy for just that reason.
My layout uses David Barrow style “domino” segments each 2’ by 4’ bolted together and each as a flat plywood top. Above that I have “subroadbed” of 1/2 inch homasote or plywood, or, in some places, 5/8" plywood. The subroadbed is cut to follow the straights and curves of the track, so it isn’t like simply laying another 2’ x 4’ slab on top of the benchwork.
Above that subroadbed I have the usual Atlas or whatever brand cork roadbed. On some sidings I use N scale roadbed for its lower profile.
Here is why I do it. I model the midwest which is mostly flat but with some variation in profile, some rolling hills, culverts and creeks, etc. If it was just cork roadbed on plywood, that plywood would be my “ground zero” and I’d have to cut into it for anything below that. According to my HO scaled caliper, the Atlas cork roadbed is scale 1’5" thick. The homasote is scale 3’3" thick. The 5/8" plywood scales to 4’4"
So that gives me several feet of depth below the track that I can use for culverts, gentle hills, perhaps a pond while retaining the basic plywood base.
When I need something much deeper such as a gravel pit or creek, I lower the entire domino top. This way I avoid using the cookie cutter approach – and the reason why is that with 2’ by 4’ dominos the underframe bracing and 1"x4" pine sides make the cookie cutter approach a little impractical is you want to go down below the basic level of the table top, rather than lift it above.
Dave Nelson
Nah, not necessary.
Rich
Thanks everyone. I have to erase the pencil lines because they will be in the way of the final diagrams, and the block sander works great!
I got a idea though about the one section. I may use a open grid benchwork with a subroadbed curve and incline. So I can place hills and some rocky terrain and a nice creek, then a removable section at the door and on the other side of the room have the layout higher and include a staging yard, which brings me to my next question. That is for what I understand it to hide the cars from view to simulate fresh loads from another yard correct?
I agree with Cowman. Painting or otherwise sealing wood, plywood, Homasote and any other “absorptive” materials (on the edges, too) is an effort of modest cost and time to mitigate the absorption of moisture. Obviously, its necessity varies with the location and its environmental conditions, but every location has a certain amount of humidity (or lack thereof), and sealing is an excellent precaution.
Dante
I have a 25’ x 42’ layout in a Midwestern basement. Most of the layout is 3’ wide supported on a 2 x 4 framework, and the surface is 1/2" plywood. I have never sealed either side of the plywood, and I have never had a problem with warping. I can only relate my experience.
Rich
Hi,
My layout is in a spare room - completely temp and humidity controlled. About 3 months after laying out the track (11x15 HO), I walked in to find about a dozen kinks that “came out of nowhere”.
The problem was plywood shrinkage, as all of a sudden I could see very small gaps at some of the seams. A couple of the spots had to be relaid, the rest responded beautifully to a slice with the Dremel cutoff disk.
It is my belief that the wood was “wet” when I installed it, and gradually dried out over the three months. I thought leaving it in the insulated attached garage would address the potential for shrinkage, but obviously it did not. My thought is that it was especially green (wet) when I bought it.
Richhotrain indicates he didn’t seal his wood and didn’t have any problems, and I suspect the wood he got was relatively dried and aged - which is a good thing.
For what its worth!
I should add that I buy a higher grade of plywood, one side finished smooth, from a lumber yard in my area, not the construction grade from Lowes or Home Depot.
Rich
LION used 80 year old Celotex Panels. They used to be the ceilings in some of the buildings that we tore down. They were thoughtfully saved in the gymnasium (warehouse, nowadays) until I found them.
I found them to be completely stable, easy to work, and I used them without any sub-board.
You take what you can find!
ROAR
I purchased the milled lumber for a new layout a week ago. I cleared out a space in the garage, arranged items so that I could prop up and spread out the lengths of 1 X 4 and 1 X 2, and nine sheets of 1/2" plywood of sheeting grade, and plugged in the trusty dehumidifier. I have emptied the reservoir twice since then, and will not cut an inch or drive a single screw until I pull at least one more full reservoir of moisture out of that wood.
Later, once the layout is erected, I will continue to keep the humidity between 50-66% using a comination of heat and dehumidifier.
Having said that, I can’t disagree with the idea of sealing any wooden materials used on a layout. For some, it makes abundant sense to provide whatever barrier to moisture one can offer his/her handiwork, particularly when you understand how critical it is to have trouble-free trackwork for full enjoyment of one’s layout. On the other hand, if you are a lazy sod, as am I, …[:D]
Crandell
This thread has become a “should we seal the plywood or homasote” thread which is just fine.
I bought my initial plywood as well as most of my dimensional pine at places that stored it indoors. I have had few if any problems with it but I do have to say that my “Domino” segments mean that there is probably a greater concentration of screwed together framing and overall size is controlled so there are fewer opportunities for warping.
Also I bought a great deal of my materials all at once. That means that a great deal of if was in my basement through several changes of season before I used it for layout purposes. That also probably limited the warp factor. And while it was stored it was layed flat, not leaning or allowed to sag.
So the takeaways seem to be how the wood is stored before and after purchase, whether it is given a chance to “learn” the climate of the room it is going to be used in, and what size and expanse and what kind and extent of framing you are going to employ. I did paint the flat tops of my benchwork brown but more to give me an inspiration for what it could look like – I found I was losing steam so to speak by seeing a vast expansive of plywood.
For homasote, even where I bought it indoors and let it season in my home, when it came time to use it, I sealed all surfaces and every edge with shellac – chosen because an old article by jim Hediger pointed out that while it is liquid, it has no water content. Apart from the smell I liked how it worked, but it does make the homasote pretty crisp something to keep in mind if you intend on hand laying track on homasote.
When I needed to get some fresh 2" x 2" wood for legs, I found my favorite place no longer stored it indoors so I was in the outdoor (brrr) lumber shed to pick it out. It was hard to find pieces that looked OK to me at the time but when I got them home to a heated ba