Road bed for Modules

Discussion in 'Modular Layout Forum' started by stump7, Jun 15, 2005.

  1. stump7

    stump7 Member

    Hi Folks

    I am a newbie to modular railroading. My previous layout was a moderate sized double deck affair using traditional L girders, plywood/homasote roadbed carried on wooden risers. I’ve followed the links found on this forum and used all the great information available so I now have two module boxes 30” x 72” built and filled with foam board. However, I can find nothing so far on the next step, laying down roadbed. Does one use a plywood base with homosote over the foam? Does one glue just homosote to the foam (what about warping?)? Or do you just glue the track directly to the foam? How does one treat elevation, which I will have since I am doing a logging scene? Any suggestions or leads to information would be greatly appreciated.

  2. Yard Goat

    Yard Goat New Member

    Forget the Homasote and plywood. The whole point of going with foam as your base material is to reduce the weight of the module, allowing for easier setup, teardown and transportation.

    First thing I would recommend is painting the entire top deck of your module with brown or tan latex paint to cover the pink or blue foam. Painting the whole module inside and out helps to seal moisture out and is easiest to do before you lay track.

    You can glue track directly to the foam using Liquid Nails or yellow carpenters glue--not white glue, since that can dissolve if you use water-soluble techniques for ballasting and scenery. Glueing the track right to the foam is easy and gives you a flat track profile which works for yards, industrial trackage, logging lines and the like. The main problem with that approach is that trains rolling over your module will make a lot of noise as the foam resonates with the track.

    For a mainline ballast profile, glue cork roadbed to the foam, paint it and glue the track to the roadbed. On my modules, the track plan has been in flux so I pinned the track down using ordinary dressmaker's straight pins that sink through the cork roadbed into the foam and anchor the track pretty well. Long-term it will all be glued. The cork reduces the noise of trains moving over the module (not as quiet as with Homasote, but so much lighter). Some people cut trenches in the foam using a hot-wire tool and sink the cork into the trench so it sits level with the deck. This gives you the sound-deadening of the cork, with the low profile of track laid on flat ground.

    If you want scenery that descends below track level, you can glue an extra sheet of foam beneath the one your track sits on and use a knife or a hot-wire tool to excavate the foam. This works for scenes up to the depth of the module frame. For elevations above the baseline, you can just glue extra foam on top of your base and carve it how you will.

  3. 60103

    60103 Pooh Bah

    If you don't have much track, you could put down traditional roadbed (ply+Homasote) into the box and use the foam for scenery base only.
    Or look at WS rubber roadbed and glue that to the foam, then glue the track to the roadbed. Use Green contact cement -- it'e water based and won't eat the foam.
    If you plan to handlay track with spikes, you'll need the holding power of cork or Homasote.
  4. stump7

    stump7 Member


    Thanks for you unequivocal response. I had suspected that loosing the plywood/homasote technique would be the way to go, thanks for your confirmation. I certainly relate to your track plan being in flux. I know mine has too much track and looks too busy, but I can’t seem to reduce it much more and still have some operating interest remaining.


    As you can see from the above I will have quite a bit of track and I’m not into hand laying track. The foam seems to hold track nails long enough for glue to dry so that’s the way I’ll probably go. Maybe I’ll build the foam terrain first and then carve out the road bed; it seems more prototypical <G>.

  5. railwaybob

    railwaybob Member

    Hello Stump7. As AJ has pointed out, if you use homasote and plywood, you are defeating the purpose of using styrofoam for your deck so as to make a light module. And besides, plywood and homasote is not necessary.

    In adding roadbed to the styrofoam deck, I used Lepage's No-More-Nails, simply because it was not messy (like wood glue), easy to apply (if you use the tube and a caulking gun), holds the cork roadbed in place with a minimal number of straight pins (nails are not necessary), and dries very quickly within 24 hours (so that you're ready to proceed to the next step in a minimum amount of time. The only drawback is that it will take a jackhammer to remove the roadbed if you decide to change your trackplan (but it can be readily carved or sawed out of the styrofoam deck with a hacksaw).

    For some photos on how I did my roadbed (and track) take a look at this link to my website.

    If you want to add hills and mountains, you can do that by "tricking" they eyes of your viewers. That is, your trackwork remains level. However, you can build up your scenery (again using styrofoam) so that your hills will go up and down but your trackwork stays level.

    However, if you do want your trackwork to go up and down, you would simply cut the styrofoam decking around your track outline and lift it up to start your rise in elevation. This cut would have to be supported below the cut so as to maintain the elevation. Once you were raised out to the thickness of your styrofoam, you would continue your elevation by glueing more styrofoam decking - much in the fashion of the "cookie cutter" principle that is used in constructing a layout using plywood. The big difference would be that you would still maintain your light weight and styrofoam, once you get used to it, is easier and cleaner to use.

    Bob M.

    Bob M.
  6. MasonJar

    MasonJar It's not rocket surgery


    You could also use the Woodland Scenics styrofaom risers and grades. If you have or can make a hot wire cutter, you can cut your own risers/grades from the same pink or blue styrofoam you use in your decking.

  7. stump7

    stump7 Member

    Thanks for the great replies guys. Just the kind of info I was loking for. I'll spend this weekend experimenting and let you know how it goes.
  8. railwaybob

    railwaybob Member

    If you want to make your own risers and grades, you can use a hacksaw blade to cut the styrofoam. If you use a hacksaw blade (or any other blade), do it outside so that you keep the styrofoam crumbs out of the house.
  9. stump7

    stump7 Member

    I used an electric saber-saw with a fine tooth metal blade; it worked well. If you've never cut homasote with a saber-saw you've never seen a mess! Dust and particles all over the place! Somewhere in the boxes from my move I have some knife blades for the saw. I'm thinking they would work well also with no mess whatever.
  10. MasonJar

    MasonJar It's not rocket surgery

    You can also rig up a hot wire cutter (also done outside or where well ventilated). Strap 1x2 along each side as a guide to cut a straight slope. The keyt is nochrome wire - available from Woodland Scenics at your local shop. Other ingredients: old transformer (faster = hotter wire), some phone wire to hook it up, and some scrap wood to make a frame. No crumbs, no mess, no clean-up ;)

  11. railwaybob

    railwaybob Member

    Hi Stump7. A sabre saw might be a bit of overkill on a sheet of styrofoam. I've found that a hacksaw blade (without the hacksaw) works real well. And I can control the way the blade cuts. I use a router to route out the holes for my LocoNet jacks (I use DCC) and I find that to be quite intimidating. So, I try to use hand tools as much as possible.

    Just a thought.

    Bob M.

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