I've been handlaying specialwork on wood ties on extruded foam with no issues to speak of. I've also hand-laid on other materials - and they haven't minted enough money to convince me to hand-lay on plywood again!
My dirty little secret? Between the wood ties and the foam I have a cardstock track template, caulked to the foam (100% coverage) and with the ties caulked to it. Ties (medium balsa) are soft enough not to split when using fine spikes, and the double layer of caulk grabs on and holds like a drowning man's hand. Some rather complex switchwork laid in this manner has been in trouble-free service for two years now.
There's a plywood subgrade under the extruded foam, but much too far down to be reached by spikes.
Chuck (Modeling Central Japan in September, 1964)
We've spiked about a scale mile of handlaid track (mostly yard/facilities and junction trackage) directly on plywood surface, and just as much on pine spline roadbed. We have not found it particularly problematic.
For gluing the foam scenery, we just use regular white glue or yellow carpenter's glue.
Chris van der Heide
My Algoma Central Railway Modeling Blog
To the first question, I'd have to ask, how are you attaching the rail to the ties? If you're planning on spiking the rail, then the plywood will make it harder to do if there's nothing between it and the ties. Remember, the spikes we use in the model world go through the tie and into the subroadbed, which is why homosote is recommended. It's sturdy enough to hold the spikes without being so hard you can't drive spikes into it. For modeling the drainage, see the first reply above.
To the second question, it sounds like you're asking if you can use the foam as a scenery base between the sections of plywood used as a track base. The answer then would be, yes, that's what most people use it for. It can be hot glued, but hot glue has a short working time, so you'd need to do it in small pieces. For larger pieces, use a latex caulk or adhesive. If you're talking about using it as a base under the ties for hand laying, no. If you try to sike into it, it has a tendency to crush and if you are successful, in driving the spike, it doesn't hold well in the foam.
Preparing the foam to install between the plywood sections is easy and sort of resembles the old joke about whittling a squirrel from a block of wood. Precut the foam to size and try fit the piece into position. Use the glue only when it's shaped the way you want it. Larger pieces are easier shaped in place.
Question 1: The Homasote roadbed gives you a suitable spiking surface for handlaying track (assumes you spike your rails instead of gluing/soldering). The subroadbed can be anything you want provided it gives reasonable support to the Homasote roadbed, which has very little structural integrity of its own. Spiking through ties directly into plywood roadbed is usually (but not always) a guarantee of many bent spikes.
A few have had success using Luaun plywood as a roadbed. But spikes will still bend if they reach into the plywood glue layer.
One way to model drainage ditches is to use the height of the Homasote roadbed above the subroadbed. Use your favorite scenery terrain material on top of the subroadbed and adjacent to the Homasote for the ditches. Or for deeper terrain or in the case of very thin Homasote roadbed, use foam instead of plywood for the subroadbed.
As mentioned, yards and alongside tracks where train crews had to walk regularly avoided well-defined ditches.
Question 2: I have heard (and will try myself on part of my new layout) of using very thin foam (1/2" thick or less) as a scenery terrain shell. My guess is hot glue and thin foam are not very compatible; I intend to experiment with latex caulk, with white glue as a fall back. Clamps are going to be necessary to attach to underside of plywood. In my case, I generally extend the plywood subroadbed at least a 1/2" on each side beyond the Homasote. This gives me a top side attachment point for whatever terrain shell method I use. In the past, I have used plaster on window screen, and plaster cloth over cardboard and cut up foam forms.
my thoughts, your choices
Fred W
rmbarry Question 1: For the yard and engine service facility, would it be more realistic to glue the ties directly on top of the plywood and not on top of thin sections of homasote roadbed? If so, then how would I model drainage dictches alongside the track, or is that not an issue in a yard and/or engine service facility?
Question 1: For the yard and engine service facility, would it be more realistic to glue the ties directly on top of the plywood and not on top of thin sections of homasote roadbed? If so, then how would I model drainage dictches alongside the track, or is that not an issue in a yard and/or engine service facility?
Yards are flat, there would not be any drainage in between tracks. At the edge of the yard maybe, but not inside any of the yard trackage area.
rmbarry Question 2: For the remainder of the layout, can I hot glue foam underneath the cookie-cutter plywood subbase? I know that I could use plaster cloth, but I would prefer to use foam. Has anyone used foam this way? If so, can you please share any tips or tricks with me about how to properly install foam in this type of a scenario?
Question 2: For the remainder of the layout, can I hot glue foam underneath the cookie-cutter plywood subbase? I know that I could use plaster cloth, but I would prefer to use foam. Has anyone used foam this way? If so, can you please share any tips or tricks with me about how to properly install foam in this type of a scenario?
Here's how we do it at my club. We use spline and not plywood/homasote but the foam scenery is the same as you're describing. The areas between tracks are filled in with foam, and hills and land forms are shaped with foam. The foam is covered by plaster or drywall compound to smooth out the surface, then painted a tan-brown, and scenery materials applied in several layers (sand, ground foam, static grass, bushes & trees)
http://www.wrmrc.ca/construction37.html
http://www.wrmrc.ca/construction35.html
http://www.wrmrc.ca/coppercliff02.html
http://www.wrmrc.ca/coppercliff05.html
I noticed looking at yards the drainage seems to be on either side of the groups of tracks, so I would create a slope on either side of these gouped yard tracks if you want to model them at all... seems I have plenty of pictures that shows the yard tracks are the first to flood...
I believe your asking about extruded 1 inch foam board bought at the local lumber store, with adhesive caulked used between the plywood and foam? I have tried this as a sound deadener but seems I had better luck with the cork on layered plywood laminated sideways in a ribbon fashion. Seems the plywood glued in this fashion eliminates the sound waves from resonating....
I am constructing a new HO layout and I would like to use handlaid track. However, to do this properly, I know that I need to use plywood sub-base with homasote glued on top of the plywood. On the majority of the layout, I am using the cookie-cutter method for the plywood sub-base. In areas like the yard and the engine servicing facility, I am using full sections of plywood.
Thank You in Advance for your advice.
Ray