Kalmbach’s Basic Model Railroad Benchwork has a few paragraphs about using foam sheets as the bench top, glued directly to brackets below. I plan to use spline roadbed in “the country”, and the foam seemed like a good idea for flat areas like yards. You could easily carve in surface irregularities like drainage ditches. But how do you mount switch machines? I suppose you could use a plywood sheet beneath the foam. Can you use a Tortoise switch machine through a 2" thick bench top? Does anyone have experience doing this?
I have done Tortoise machines on a 1/4" plywood sheet beneath 2 inch foam. There was also an article (I am not sure where it was) on mounting the Tortoise on a square of 1/4" plywood and gluing that to the underside of the foam.
Lefty
Thanks Lefty. I went back to my Tortoise instruction sheet and I see they say if the bench top is thicker than 1" then you have to supply your own (longer) spring wire. I just wasn’t sure how thick I could go. Does the recommended 1/4" hole still work for the 2" foam?
Bill
It’s a few years old, but should answer your questions. Credit to the original author, I just found it on youtube for ya!!
Thanks for the link; an interesting idea. On the surface, it seems like more work than mounting the Tortoise on a plywood sub top under the foam, but I’ll have to think about it. I also don’t think I need 2" foam. That’s roughly 14.5 scale feet thick and I’m pretty sure that there are no 14 foot deep features in rail yards (here in central Ohio where I’m modeling anyway). At least I’m not planning any. One inch foam or even thinner would probably work fine and make it easier to mount the Tortoise under the table.
Bill
I used foam and spline for the first time on my current layout, just to try something new and different. I must say I have been really happy with the results after several years.
One suggestion I would make and would do next time myself is, I would use spline under the mainline even on the flat. It offers a substantially more solid road bed than foam. I have noticed little undulations in the foam over the years and while that is of little consequence for yards or sidings, unless you are modeling the early steam years, the little bit of rocking and rolling might not look that great.
Here you can see where I butt my spline up to the foam (lower left) and I then just glued cork road bed to the foam to match the profile of the spline. No cork was used on the spline as the track is attached directly to the spline. The two outer strips are beveled to make the shoulder profile.
I should have continued the spline straight down the bench for the mainline instead of transitioning to foam.
Here is the underside of the bench. Lots of support but still after several years, the foam is starting to dip ever so slightly in a few spots.
Here is a stretch of unsupported spline that will eventually will be cut out and replaced with a bridge. It is about 4 feet long and hasn’t sagged a micron. Thousands of little brave souls have crossed without incident. It does speak to the long term performance of spline. This has been here for years, I don’t think unsupported plywood in the same spot would have been as stable.
Bill, one question I have is, how will you be supporting your spline? You said the foam will go on brackets, you will need some sort of joist to accommodate the support for the spline.
It is just so much easier to use foam than splines. I have built large cayons even in foam.
Brent,
Very nice, I wish mine was that far along, I just bought the materials for the first section today. My intention is to use grid construction in the flat areas and transition to L-girder with joists and risers to support the spline on the grades. I’ve also decided to use 1/4" plywood under the foam which should help prevent any sagging of the foam. After reading your post, I may consider using spline all the way for the main. Not only will it give good support, it would ease the transition from level to grade. I also have a very flat “S” curve with easements in one of the flat areas which the spline would help define. Just thinking as I type, I don’t see a reason that I couldn’t fasten the spline directly to the cross pieces in the grid. There would be more support than needed given your example of a 48" span. How thick did you make the spline roadbed, how thick a material did you use, what was the material, and what was the minimum radius? Thanks for the information.
Bill
Hi Bill
My minimum radius is 32". I used 1/4" hardboard cut in 1 inch strips ( just to make the math easy) for the spline. The same stuff as pegboard without the holes. One $7.00 sheet will give you 48’ of roadbed. Seven 1/4" strips including the two outside beveled strips are what I used.
I just attached the supports to the grid where ever the spline passed over a cross member. A bit of simple math determined the height of the support when on a grade as the distance between was never the same because of the curving spline.
One thing I would definitely not do is put foam over plywood. The sagging I mentioned is minimal at most. Working through foam or plywood is easy, but for some reason I have found working through foam (feeder wires, switch machines etc.) over plywood a real pain in the butt. Although it may just be me.[(-D]
Give me a shout before you start gluing your spline together. I have some tips that will make life easier.
That little bit of plywood you see in some of the pics is all there is on the layout. It is all foam over open grid.
Thanks again Brent. I’ve also been reviewing
http://s145079212.onlinehome.us/rr/howto/splines/index.shtml
Some good tips there too.
Bill
Bill
There is lots of good information on spline on the WWW. You can also check You-Tube how to’s. People have different ways of doing things. Like so many other things in this hobby, you pick the one that appeals to you.