Spray foam

Plaster cloth could be used between the spline space but I feel it a bit messy and produce some dust, the most bad thing for our little trains.

I use red rosin paper for my hardshell, light, strong and versatile, I glue it to the benchwork with hot glue, extremly fast, I made it rigid by brushing full strenght white glue on it.

Spray foam could be an option, but you must first fill the space with a paper or somewhat else to avoid the foam to go down on the ground; second spray foam could make some pressure on the spline when drying, don't under estimate this pressure; sure it's could be messy, and again when working in form the foam when dry you will produce some dust on the layout or existing scenery.

Good luck

Spline.etc

Mike

My RR uses spline on the lower deck.  When filling in the area between spline sections I used the red rosin paper approach.  Its cheap and easy,  You'll need a hot glue gun, scissors, some card board strips and white glue.  Use just like you would plaster cloth scenery base.  You could also try strips of foam sheets from one of the big box home improvement stores.  I do not recommend using foam filler spray - messy and just about impossible to control the way you'd need.

Regarding the turnout machine linkages it would be easier to try side mounts instead of messing with drilling holes through the splines.  There are lots of options to use for these and some of the vendors supply kits for this purpose.

Don't overthink this

Don't overthink this, it's pretty simple.

First, I rip one spline down the middle at a 45 degree angle and attach one to each side of the spline roadbed to get a half-spline ballast slope to work with (slightly darker half-spline in drawing below).

Then in the middle between the two tracks, I put some masking tape, then pour a very soupy mix of plaster between them and let it set up. Easy, peasy. Just make sure there are no gaps in the masking tape you put between the tracks or you may find a nice splatter of plaster on the floor under the layout!

Then ballast as normal. This half-spline ballast slope also makes it a lot easier to attach scenery to the spline.

 

Flawlessly

Click on for large image (all).

Its 0.031" piano wire / 0.0120 hardboard (Masonite) /HO.

One more for Neil...

One more way....

Nick

Brilliant

@Nick - You just helped me solve a problem. Thanks for posting!!

Spline

Adding a 45 is a clever and useful comment. Thanks — it convinced me to try out the spline approach.

wjr123   Spine is the way to

wjr123

Spine is the way to go, don't look back. The easement on curves are great and no waste other than saw dust.

Transitions

Dumb question: How does one transition from spline to flat work as you might for a yard?

It has been years since I tried a spline roadbed and it seems as though I stated with a block attached the the riser where the plywood was attached. 

Re : filling the space..

Spline Q & A

I use homasote splines. 

The gaps between the track sections are filled in with red rosin paper with a liberal application of white glue. At a siding such as in the photo below, the spline is continuous with no gap between the tracks. The white areas are still wet, the red area has had a heavy coat of white glue applied and allowed to dry a day. 

As far as turnout control goes, in most cases there is a hole drilled through the spline with the control rod extending up through the spline to the throwbar of the turnout. In one or two cases the control rod does not go through the spline but rather is next to it. Both ways work fine.

So far, this seems to produce a good scenery base although I have just started working on scenery. 

The only problem I have encountered is expansion/contraction of the roadbed the first winter, and that was my fault for not leaving expansion gaps but rather soldering almost all joints. I went back and cut in gaps, problem solved. 

Jim

transition to spline from ply

answered here:

http://model-railroad-hobbyist.com/node/33139#comment-334632

Blair

Thanks Blair

Would you mind posting a photo of how this might look? 

Sure

Hope this helps.  As you can see, it's pretty rough-and-ready.  That's the spline just to the right of the switch feeder.  We basically hack a notch with a jigsaw and make what I would call a tang (like the tang in the handle of a knife) out of two pieces of spline by gluing the first 6 to 12" together, then glue them into the notch.  What this does is it gives us a firm anchor for the start of the spline.  As you can see, the next three on each side are just glued to the side of the core two pieces.  We generally make the two center pieces 8', or maybe one 8' and one 7'.  The outer three on each side are progressively shorter, so that we end up staggering the joints by between 8 and 12 inches per.  The actual progression of adding layers is pretty panicky, as you don't have a lot of time to apply hot glue then clamp.  We usually glue one strip at a time, moving along the strip with the tip of the glue gun shoved into the open joint, and the second person wielding the spring clamps just as fast as he can.  Speed of production is governed by how fast the glue gun will melt the glue stick; if I could double the wattage of the gun, we'd start to hit the limit of what we could do, but as it is we're doing okay.  It sounds complicated, but you get used to it quickly.  We did about 200' this way on my old layout, and we'll do more than twice that on the new one.   I'll try to take some pictures during the next production run.

Blair

@ Neil

I started the grade transition with plywood and when it got high enough I converted to spline.

when the terrain demands a change, back to plywood.  I supported the plywood every foot and the spline every 18” to 24”.

Nick

Transitions

Blair & Nick - thanks for the pics. I can see the advantage of notching the plywood to receive the spline and it would force an easy vertical curve. Nick’s version works too but careful tracklaying to avoid an abrupt change would be necessary. 

As ridiculous as this may sound, I have been considering raising the railroad height of my garden railroad for better access. A plastic spline built up as you have done indoors could work with frequent supports. A wire mesh and a coat of mortar mix would form the ballast slope and adjacent terrain that should (I hope) weather better than simply floating the track on the roadbed at grade. 

Outdoors

Neil

I think a plastic spline assembly of some form would work well outdoors.  I'd look at the costs, though - if you're running 1:29, I'd expect the spline assembly to need to be about 6" wide, with radii exceeding 6'; 8' material would mean a lot of joints, too, so I'd look for a material that's available in longer lengths.  something 1/2" or 3/4" thick would mean fewer layers, too.  Ideally, maybe something 3" x 1/2" x 100' in a roll?  To fit that form, it might be some form of accordion, or kerfed along the back edge, to enable curving and reduce material volume.  Of course, it doesn't need to be a solid assembly.  Lots of people use the spline technique with every second layer being spacers, to reduce the volume of spline material required.  We tried that, and may again.   In our masonite spline days, we didn't get good adhesion on the spacers due to a gloss face on one side, so we simply stuck with full spline.

I emphasize I don't know what materials there might be out there, so I'm just dreaming; there might also be something in the building materials line similar to the foamcore poster board, but with better environmental qualities.

Good Luck!

Blair

Spline

Nick

So you're using a central spline, but capping it with a flat sheet of ?masonite??  How do you keep the horizontal material from tipping left or right - are you adding intermittent shoulder blocks?  I can see marrying our techniques, anchoring the central spline as I have done to force a smooth transition, but capping it with flat stock, and not having to plane the top surface.  But you still have to cut the flat sheet stock to follow your curves, it's just in a thin material, not ply.  That's why I don't use plywood curves cut from large sheets - I've found it very wasteful.

To each his own, I guess, though I'm tempted, for a straight section, to try the marriage.  Most of my straightaways, though, are plywood, as they're interchange yards, yards, or triple-track passing points, so I won't see much gain.

Blair

Spline In the Garden

Garden modelers have been using splines to build elevated road beds for many years. The splines have been made of various materials, but wood seems to be the most popular. I ripped 3/8" x 2" strips of cedar for my layout in New Hampshire. I have also seen pressure treated wood strips used.

After planing I treated the strips with an penetrating insecticide followed by a couple of coats of thinned poly wood sealer. The strips were glued together with a marine polyester resin, and the spines were painted with two coats of a medium gray UV resistant marine paint. To save material the ~4" wide splines were assembled with six cedar strips with 3/8" blocks between strips and nailed with SS and brass brads and screws. The marine resin and paint were probably overkill (expensive stuff), but I had some left over from working on a boat, and it lasted for more than a decade without any rework. I can not say the same for the purportedly ground contact rated pressure treated wooden posts I used to support some of the spline. The posts started rotting after about seven years requiring replacement with sections of exterior plastic wiring conduit. As with any outdoor construction for stability the posts need to extend below the frost line.

I have run on a raised layout that was built with splines made from wood filled plastic material used for building decks. It was OK in cool to moderate temperatures, but when it got above 85 F the splines would start to sag and twist.

@Blair

Here’s some pictures of what I did.

I cut sections of the Masonite on angles to fit the corners.  This section doesn’t matter for scenery.  I could also come along the sides of the top with a jigsaw or a Dremel vibrating tool and smooth it off.  There is enough of a lip to attach the scenery surface when the time comes.  I was too cheap to buy enough Masonite to do solid spline and had a lot of small pieces of plywood to make spacers out of.    Next is a view from the bottom.

Next is a view of a long straight grade (1.2%) of about 36’.  The spline continues onto the cabinet “wood yard.”

Someday it will be more finished....  curved ME weathered track with separately hand painted ties but no ballast yet.

Nick

P. S. I used yellow carpenter’s glue and clamped the spacers to the Masonite.  Then I used the same glue on the top for the piece of Masonite.  If you look hard you can see the super elevation shims between the cork and the ties.

Spacers

Thanks! I’ll make a trip to the big box store. The idea of spacers is appealing and, yes, it looks like a lot of material. Including the bridges I paced off about 240’ of mainline. Slightly over a scale mile. I’m leaning toward some plastic “wood” but hadn’t considered the heat being a factor. I have some 3/4” x 1-1/2” material that may risky bending in the deep dimension of supported frequently. 

Ken - Were your ties fastened to the spline or was there a flat base on top as Nick has done? Since the idea is to get the ties off the ground for drainage and a little easier access I like the spacers and can fill between with gravel. 

 "How does one transition

Hi Neil, I prefer to join them with a length of splice material underneath. If the ply/spline joint is in a vertical curve transition the splice plate can be laminated to conform to the needed curve. Since the plywood and the splines are not usually the same thickness a spacer is typically needed between the bottom of the ply and the spacer plate....DaveB 

Bender board?

Our local lumber store sells a plastic product that is intended to outline garden beds. I've had some half buried in my yard for years. It is very flexible and cuts like  wood. Various sizes are available, mine are 1x5 with a fake wood grain pattern. I can rip it on my table saw-- a 1/2 inch slice bends to a 12" radius.

Not sure how you'd glue this stuff, but I suspect you could just clamp some pieces into a spline and secure it with decking screws.

I see similar products made of pressure treated redwood.

pqe

Were your ties fastened to the spline ...?

Neil, Some of the track (with ties that were not attached to the rails e.g. LGB and Accucraft) was screwed to the splines, but due to the temperature excursions in NH I used cable ties and SS wire to loosely hold most of the track in position. AristoCraft track with the ties screwed to the rails can really buckle if you screw it down. Even most of the switches "floated" on sections of man-made window sill material (some sort of polymer filled with stone dust we found at a local "stone" supplier). Some of the switches were held in place with a little exterior caulk which had enough give to survive the temperature extremes.

Blender Board

Pelsea, Thanks for the comment. Several manufacturers seem to make products labeled Blender Board, but the Island Blender Board products do look promising. They seem to be available locally, so I will try to purchase some for testing to see if it could be used for making spline. I also need something to help with retaining the ballast on sections of the Museum layout.