Suggestions for track on foam?

[memsd]

I'm getting started on my first layout. I've decided to do all of my levels on foam. My question is what do I need to put between the foam and the track?

[Anonymous]

Congratulations!

I would recommend a roadbed such as the cork roadbed sold by various places like Midwest. I believe Woodland Scenics also has a foam roadbed, not the same material that you're buidling on, which would be the subroadbed. Depending on how you want to ballast your track, you can either put the tracks on the subroadbed with glue (dilute white glue 50/50) or you can put the roadbed down with the 50/50 glue and then glue the track on top of that.

Advantages of putting it on a roadbed
- greater sound-deadening properties, although you are building on foam, so it's not that big a deal
- raising the track above the level of the foam is more prototypical, as railroads want to have as much drainage away from the tracks as possible.
- when you put ballast on the track, it will follow the contours of the roadbed and you won't have to use as much ballast material to "fill" in.

disadvantages:

- you have another piece of stuff you have to glue down or take up if you decide to move it.
- cost, although the foam seems to be cheaper than the cork.

there are other advantages and disadvantages, but those are the most important ones I could think of.

[cacole]

Assuming that you're talking about flex track and not hand-laid, you might want to use either foam or cork roadbed to elevate the track in a more prototypical fashion than just putting it directly on the foam.

[memsd]

No, I'm not ready to try hand-laying track. The foam roadbed can go directly on the foam risers? That's simple enough...

[orsonroy]

Adding cork, foam, etc., roadbed on top of an existing foam layout base is wholly unnecessary. Roadbes is ONLY a scenic element, to give your track profile a more realistic appearance/ That's fine, but why bother when you have a perfect carving medium (foam) aleady down? Just lay the track directly onto the foam base (using a water-based adhesive, contact cement, or scilicone adhesive caulk), let the glue dry, and carve the foam.

My layout base is 2" foam. Instead of buying roadbed, I'm using 1-3/8" wide strips of 1/2" thick foam. I can get 150 linear feet of roadbed out of a $6 4x8 sheet of foam, and it takes seconds to carve properly. I get a realistic track profile and I'm saving a wad of cash in the process.

[memsd]

orsonroy: Do you use the WS foam risers? If so, what do you use to cover the gaps?

[orsonroy]

I don't use any of the WS foam materials. Since I have a large three-level layout, I'm using my bracket supports to move the benchwork up and down grades. All my subroadbed and scenery is extruded foam (not expanded, like the WS stuff), so I just cut and carve everythign to shape, hiding gaps by filling them or hiding them under bushes.

If you're working on a smaller, tabletop layout, I'd suggest using the WS risers, since trying to carve a smooth grade out of foam is a time-consuming and frustrating mess. I'd butt up extruded foam to hide the gaps in the sides of the risers, and add an overlay of 1/2" thick extruded foam on top to hide those gaps (narrow strips of 1/2" thick foam - under 1.75" wide - are very flexible and can be curved to conform to your mainline).

The traditional method would be to use plaster cloth of some sort to hide the gaps (what WS recommends). I don't use any plaster on my layout at all, since it adds weight, cost and mess, and because the plaster overlay isn't as durable or strong as plain extruded foam.

[johncolley]

Does anyone have any experience with Goodyear Pliobond on foam? I am thinking of using it to help reduce sound transmission. Maybe the adhesive caulk is a better way? johncolley

[orsonroy]

John,

It seems loke the caulk would help deaden sound on foam, since it's "springy", and acts as a sound baffle. Frankly though, the best way to deaded sound and the drum effect on foam is to laminate plywood (1/4" will do) to the underside and to fully scenic the top side, including a couple of heavy coats of latex paint. Adding a layer of plaster to the top of foam also greatly reduces foam noise, but I don't see the point in adding plaster to a perfectly good foam surface.

[memsd]

Thanks, orsonroy.

[Anonymous]

I have had great sucess using Cork Roadbed. The problem of "carving" the ditches, is the rail will always be at the height of the surrounding "level" unless you are scoring away A LOT of foam.

All of that aside, I use liquid nails to glue the cork down. It is tacky, so your cork "sticks" and can be pushed or pulled in line with your trackplan for five minutes or so.

It also is not a water based glue, so the cork doesn't deform and pull away. It literally sticks flat. No need to tack, or staple (however I do employ weights or objects to help adhere in tighter curves.)

The Liquid Nails or generic substitute also seems to insulate the sound until you ballast... however, when you go back the next day and lay track, you should use diluted white glue to secure the track after "tacking" it here and there to keep the track in the center of the cork. After a day or so the track is solid and won't budge, making it much easier to work around and even ballast at a later date.

My thought on the sound issue changed after ballasting long sections. The ballast and white glue hardens like a rock, and seems to transfer the sound to the foam board, (albeit not as loud as without the cork.)

[orsonroy]

QUOTE: Originally posted by mdemt
I have had great sucess using Cork Roadbed. The problem of "carving" the ditches, is the rail will always be at the height of the surrounding "level" unless you are scoring away A LOT of foam.

That's why a lot of modelers who are using foam as a layout base are putting down a layer of 1/2" thick foam as a semi-subroadbed. Adding the 1/2" foam onto the foam base gives you a bit more rise above the base laver, and you can add commercial roadbed (cork, etc.) on top of the 1/2" to give you your final profile. This technique works especially well when you're modeling the Midwest, since the ground undulayes a lot, but the grade profile stays relatively level. If you need to bring the surrounding scenery up to track level, just add some larger pieces of 1/2" thick foam.