"Depressing" foam board?

StrasburgNut Dec 5, 2008

  1. StrasburgNut

    StrasburgNut TrainBoard Member

    Is it more feasible to "drepress" or cut into and down on the blue insulation board and have the rails follow that contour than making sure you have enough length of track to have a 2.0% grade?

    I want to have a few operations in the mountains on my layout. So, rather than having the grade be a tad bit steep to get to a minimum of 2" clearance between the zero elevation track and the bottom of the bridge that track will go under, couldn't I "depress" the foam to go down, have the zero elevation track follow that drop so it can make that 2" clearance?

    Just curious if anyone has done this and how they went about it. I am sure someone has.

  2. Grey One

    Grey One TrainBoard Supporter

    I have found that trying to cut smooth declines or inclines in the foam can be tricky. I have:

    1. Laid my unitrack down
    2. Traced it
    3. Cut that piece out and then supported
    Yes, it worked and seem ok though I never felt it was secure. That could just be me and my construction skills.
    This was done using that method:
  3. StrasburgNut

    StrasburgNut TrainBoard Member

    I was thinking of cutting out the 'width' of the depression and then sanding it down with one of those sanding sponges, or using a rasp. To "smooth it out", I could put latex caulk on that area to level it and the paint it, apply roadbed, track and ballast. This is my thought process on it.
  4. BarstowRick

    BarstowRick TrainBoard Supporter

    I have to give you high marks for trying. And it looks good. I do admire you for attempting to build a duel level railroad with a foam sub-roadbed.

    One thing that might help, where the foam sub-road bed meets or abutts, try a piece of flat foam to overlap both connections (on the bottom side) securing the two pieces of foam sub-road bed with a flat piece underneath, using some of the new CA's designed for foam or other various types of quick drying foam glues. The foam on the lower level will need to be tied down to permanent bench work and then bend the foam upwards via risers.

    I connect my particle board sub-roadbeds in this fashion and you can see it on the invite to my rail images below. This shows off my favorite way to build and I think the techniques I use can be utilized, with foam. The weak point appears to be the risers. You could use a 1x4 wood support, but I'm not sure that would give you or I what we want.

    The only thing I would worry about is if a youngster or adult should visit your layout who has a poor sense of balance and accidentally falls on the layout or a arm gets a little heavy and drops on one of the upper levels. You would then need to call out damage control.

    Here we go: I have a friend who built his duel level layout by filling in the areas underneath the foam sub-road bed with flat foam supports (one piece of flat foam placed on another).

    Like you I wouldn't feel secure with the risers as pictured. I'd want something stronger.

    If it isn't obvious I was confused by the lack of a question. Still the advice I shared here may be helpful.
    Last edited by a moderator: Dec 6, 2008
  5. COverton

    COverton TrainBoard Supporter

    I'm not quite sure I understand the question, but it is quite acceptable to split the difference when an overpass of track by overhead track will result in a very steep grade to get the right clearance. If the rise up and then the drop back to level will be anything over 3%, your models will struggle. So, why not have the nether tracks depress on a slight grade to the overpass and then rise back to the first level on the other side...say at 1.5%? Similarly, the track climbing to the overpass will only have to climb at 1.5% and you have your solution...including the necessary clearances.

    Foam does sand well, and you can make ramps with it, but it's a pain. You would probably be better off using the graduated height pylons from Woodland Scenics or use 1/8" masonite or doorskin cut to width and length to form an eased grade. You cut it long enough so that you can scour out a bed the right depth to make the masonite fit at grade in the foam surface, glue it into position for about 8", and then bend it up into your grade. It will form an easement naturally, and you can support it as a sub-roadbed with custom carved chunks of foam pylons every 6-8". At the top of the grade, reverse the easement into a glued length into an upper structure, perhaps stacked foam.
  6. dstuard

    dstuard TrainBoard Member

    One of the key benefits of foam is its ease of carving into various scenery shapes. Unfortunately, it is very difficult to carve a smooth and consistent ramp into a piece of horizontal foam. As some have suggested, it is easier to bend the foam board itself (or doorskin) to get a consistent grade. Personally, and since smooth and stable roadbed is a must for reliable trackwork, I would either use Woodland Scenics risers, or go the cookie cutter route with doorskin or 1/4" plywood subroadbed and leave the foam for the scenery.

    Also rather than thinking "up and inch, down an inch" from your foam base, consider that your railroad base is at -1 inch, and everthing is above that (including most of your scenery).
  7. okane

    okane TrainBoard Supporter

    I use 1 Inch Foam board in conjunction with the Woodland Scenic risers. I use the 2 inch foam board when I reach two inches.
  8. sootower

    sootower Permanently dispatched

    Foam instead of wood?

    What was the advantage of using foam rather than (ply)wood for your subroadbed and risers? Your trackplan appears to be perfect for using the 'cookie cutter' style of subroadbed construction.
  9. Mark Watson

    Mark Watson TrainBoard Member

    I'm about at the same building stage as you are, but I'm choosing to go with the woodland scenic risers and incline pieces rather than carving the grades straight into the foam. My reasons are simply that I've carved them myself before and was very unsatisfied with the result.. which took a few days to achieve.

    After that experience, I'm a strong believer in using woodland scenic risers and incline underneath your foam sub roadbed. It gives you an exact grade that is completely smooth. You can even control things like grade easements by "stretching" the incline at the beginning and end of the grade. Just make sure you have plenty of weights while gluing the sub roadbed to the risers so that places like the beginning and ends of grades follow the contour of the inclines/risers and don't "bubble" up.
  10. Benny

    Benny TrainBoard Member

    The advantage is you only need a utility knife and toothpicks and glue to make it out of foam.

    Plywood takes a powersaw and all sorts of wood working talent...pounding, drilling, screwing, et al.

    The WS inclines are worth every penny you spend on them. I found they glue down well, and I stabbed toothpicks through the sides and into the foam subbase to keep them in place while draying. Later, the toothpicks were left in. I use the buttend of a sharpie marker to drive the toothpicks in, as it has a dimple that makes this easy.

    I later discovered the incline pieces are even better when you lay a layer of foam on top of the incline, which really helps out the grade transitions.
  11. trobins

    trobins TrainBoard Member

    I use exactly the same method (see pic), but I use a LOT more support under that top layer. I learned (the hard way) just how easy it can be to put too much pressure on things while working on them. Note that I am using cheap white beadboard (messy), and I find plain old Elmer's white glue works best. Toothpicks hold everything in place until the glue is dry, then I pull them and reuse.


    Attached Files:

  12. Grey One

    Grey One TrainBoard Supporter

    The advantages were and still are:

    • Cost
    • I do not have power tools to cut the plywood
    • Due to visual limitations I do not drive - cannot get plywood to my place
    • Nobody told me I couldn't do it - then again I probably would not have listened. it might have been more succesful had I used reinforcement as suggested. I lost my confidence and went with a flat layout.

    • I have visual limitations (legally blind) and hesitate to use any power tool except for drill or screwdriver.
    • While I welcome advice I need the logic / reasoning behind it. With that I can find ways to overcome limitations. For example the old adage about never exceeding 2 percent grades. I have successfully done 6 percent with DPUs in the center of the train, (as in the picture provided).
  13. Benny

    Benny TrainBoard Member

    Tim, imagine another layer of foam on TOP of the inclines in addition tot he foam UNDER! That is where I was when I finished with foam. I say I am finished with foam because I really don't like how flexible the track is in foam and I like how plywood really holds spikes.

    This means future layouts will be harder to build, but they will be stronger and the modules will hopefully survive more abuse.

    I found that simply sliding the toothpicks home is the bet route to go. Its easier that way!!
  14. StrasburgNut

    StrasburgNut TrainBoard Member

    Some real good advice here. Thanks to everyone who replied.

    Looks like I will be getting a 1" thick sheet, rather than a 2" thick sheet of foam. Makes more sense to do it that way and cut the 1" as needed

    Better than sanding and having static cling blue dandruff!:mbiggrin:
  15. Shortround

    Shortround TrainBoard Member

    A lot of food for thought. I don't know when I will be abile to get started but I'm getting a lot of good ideas and information.

    Thanks for letting me hang around. As soon as I can get a job that lasts I will be picking your brains. :tb-biggrin:
  16. Benny

    Benny TrainBoard Member

    For your grades I would advise getting hte incline pieces and then getting 1/2 inch foam. it curves vertically beautifully, which means your transition hump will be smoother.
  17. rkcarguy

    rkcarguy TrainBoard Member

    I've cut on either side of the tracks and pulled/flexed the surface down to give me my underpass clearance I needed. You can make little dropped supports for underneath or just glue it in place if you use foam.

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