I’ve bent the 1/4" thick spline to as small as a 12" radius, which is way sharper than anyone will need in HO unless you’re building a traction layout. For N scale, 1/8" thick spline will allow a 6" radius, again, much sharper than you will likely ever need.
The other thing that hasn’t been mentioned so far as an advantage of the spline is vertical curves. With the traditional plywood/homasote sandwich roadbed, it’s quite easy to make a change in roadbed grade that’s too abrupt and can cause derailments and poor tracking of equipment.
Spline is thicker vertically and makes it hard to do abrupt changes in roadbed grade. As a result, spline roadbed forms appropriate vertical curves naturally, making it great stuff to work with.
I follow all of this. One issue that occurs to me: what do you do for vertical easements? I can see where curve (horizontal) easements that the spline is ideal–just bend it to whatever easement curve you want. But what about vertical easements–no way you’re going to bend that spline roadbed in that direction/axis–just use a short section in transition before the start of the grade spline?
Trust me on this. There is no problem to do vertical easements. You begin with 2 splines, glue them together (in the right shape) and let the glue dry. Then you add the rest of the splines, all at once or one by one. The splines will stay in the shape you gave them when the glue is dry. We are talking of prototypical easements now, no roller coaster.
Neat jobs, all! Re the radius, I believe Joe used 24" min.,so check if you want 22" make a mock-up. It might help to dampen (don’t soak masonite) the splines overnight before bending. The beauty of the spline method is seen in natural transition curves and also in grade changes. I personally prefer really big curves so that trains flow around them. Really study a few photos of trains on mainline curves, even in the mountains, figure the average car length, and count the cars on just the curved portion of a 45 or 90 degree curve and you will be surprised when you see what I mean. As low as 72" is a tight curve and on the prototype might even call for a speed restriction. Also note that curves often look tighter due to telephoto effect of flattening. jc5729 John Colley, Port Townsend, WA
The secret, for me, was orienting the tops of the risers. If you get their heights right, but also their cant, you will find that laying spline roadbed is a dream. As EL says, and Joe long since knows, the process of laying two or three at a time allows the individual sections to conform to the gentle changes in orientation that adhesion to the riser surfaces forces on them. By carefully varying their heights and tilts, the splines must perforce adopt the necessary horizontal and vertical curves that you have designed to get the elevations and nice lines you envision. It does take planning, it takes a bit of learning to get the feel for how it all should come together, but once you get a six or seven spline section screwed into place, the rest is just an exercise in patience and pleasure.
Spline from now on for me, or else it will be flat bench type layouts in the future.
P.S. - a critical step…not to be missed (!)…is to plane or smooth the completed splines before you place the track sections. You won’t get them to line up perfectly, no matter how hard you try. So, before you start laying the track, use a surform file and do a decent (unhurried) job of making the surfaces nearly planar. You’ll be glad you did.
The spline forms natural easements both from tangent to curved horizontally, and from level to grade vertically. In short, it’s close to perfect when it comes to forming smooth roadbed naturally.
The one caution is to watch the side-to-side level of the roadbed. It’s easy to twist it out of level, which can cause you to have superelevated track when you didn’t want it to be so, and even worse, the side to side level could alternate from riser to riser so that your equipment would rock badly as it goes down the track.
To counteract this side-to-side leveling issue, I use a nice long 2-1/2" drywall scew to anchor the roadbed down into the riser well and I counter sink the hole deeply in the spline so the screw head is below the surface level of the roadbed. I also prefer a 2x3 or 2x4 riser so I have some extra width in which to put screws when attaching the riser to the benchwork joist.
I don’t anchor the risers in place until after I have attached the spline roadbed to the risers. Then I use a 9 inch level to check the side-to-side level of the spline, clamp the riser in place, and adjust its position until the spline is level. Once everything looks good, I screw the riser to the joist with drywall screws, using at least two screws per riser, out near the edge of the 1x3 or 1x4 riser, so it’s held in place well with good leverage and won’t shift later.
This sometimes gives me risers that are not perfectly vertical and perpendicular to the joists, but it gives me flat and level roadbed, which is what I’m after. If I later want to superelevate a curve, I use stripwood shims. Since I know the roadbed is level, then I can trust the superelevation added with shims to be correct.
I can intuitively see how the splines would make going side-to-side easier / more natural looking. But how do you go up or down a grade? I can see it going up a grade in the picture above but how do you bend it in the direction of the strength of the spline?
My splines are 240 cm in length. To make it go up ur down a grade just bend it. One single spline is no problem to bend, it almost bends itself (in ALL directions). When all 7 splines are glued it will not bend anymore, it will hold the shape you gave it before gluing. 7 splines glued together is VERY strong and will give you a massive roadbed. I can’t think of a better way to build roadbed.
May I suggest you buying a very nice DVD from Joe Fugate that shows you how to build spline roadbed. I think that’s better then trying to explain it with my crappy english. I’m from Sweden you know. This is the url:
As a owner of a cabinet shop and cabinetmaker, I find it interesting all the different materials and methods that is used to build a layout. Depending what hardboard(massonite) you are using, there are some inheritant problems with both types of hardboard. Tempered HB contains oils that will cause glue rejection, and standard is soft and prone to expansion problems caused by hummidity. The requirement of clamping time for the adhesive to set up is at least an hours time, depending the type of adhesive you use, plus a large investment in clamps! I find it not a good choice.
I have been operating on a layout for 3 years that is splined with Homasote with hand laid track. It operates to complete perfection. Derailment are rare and usually are operator error. His bench work is extremely simple! He has no L girder construction and is just cantaliver arms hang on the wall, and has spans between cross members up to 48". The homosote has more than enough strength to span these distances. The cuves do require a plywood strong back to keep them consistant radius. The road bed also is free floating on the benchwork. His yards are also spline Homosote. They are sized from 24" x 240" in length. The use of gypsum board(sheetrock) is not advised. It has very poor fastner holding ability, paper has poor glueing capabilites, it is also has a moisture asobtion problem and it will sag over time.
The other great thing about Homosote spline, it requires only on person to do it, and if you don’t like the way a curve or a run looks. All you hve to do is remove the screws and reshape it, reusing the sam splines and screws.
I have done some cost research on Homosote Spline verses 3/4" Birch Plywood/Homosote flat surface. I have found that the Spline is about half the cost as Plwood/ Homosote. When you factor of a 25% waste factor on the latter! A sheet of H
For those reading who are still scratching their heads over the curves, both horizontal and vertical, the idea is that the position of the very top face of the risers determines the “attitude” of the first, and subsequent, spline layers you put atop them and then glue together. The splines are less than 1" wide typically, say 3/4" on the narrowest to 16/16" in my case. They have been ripped from 1//8" or 1/4" stock, whether masonite or MDF, where I used the latter. The spline pieces are ripped from full sheets. So, I got a whole bunch of these long floppy sections from a single sheet of 4X8 1/4" MDF. After figuring out your riser top positions to get the grade you want, any superelevation on curves, and so on, you drive a 1.5" wood screw partway into the top of the riser, straight down into it, with the hole being on the centreline of your trackplane (you will have taken the trouble to map this out and actually marked the tops of all your risers to help you to keep it all aligned.)
Next, you take two or three of these long floppy sections, slather a bit of glue on one side so that the three will stick together, and use at least 6-8 small clamps to keep the sections from spreading apart, especially along curves. It is in the clamping and keeping these sections touching the tops of the pre-positioned risers that makes the spline begin to conform to the grade transition you have in mind, and the curves. You can’t really manage to glue all 6 or 7 sections together at once, and for sure after they are dry, you haven’t a snowball’s chance of getting any change of shape in those six plys. So, you start with two or three, easily pressed into nice horizontal and vertical curves, clamp 'em firmly to make them stay put, and wrap them tightly around that screw you placed on the centreline that I mentioned. Those screws serve as anchor points around which you force curves…they’re pivots.&nb
Unbacked homasote or MDF will also sag badly between joists. If 1/2" plaster wall board is backed with 1/2" plywood, it’s just as good (or better) than homasote for flat areas and works great.
The wall board takes latex caulk for track laying very well, and it holds track laying spikes fine. It will not hold screws well unless the screw is long enough to bite into the backing, but that’s somewhat true of homasote as well.
My layout is going on 17 years old and my flat areas of plaster wall board are holding up very well. I use moisture when doing scenery work, and the wall board swells less than water soaked homasote does. Also, I’ve never had a humidity problem with the plaster wall board in 16+ years of the layout’s existance, and I would use it again in a heartbeat for large flat areas.
If moisture is really a concern, you can also get green board, which is plaster wallboard made for use in bathrooms. It’s still way cheaper than homasote per sheet and is more resistant to the effects of moisture.
About 30 years ago I used a somewhat different form of spline roadbed. I took two 1/4 inch by about 2 inch strips of wood, seperated by blocks of wood, attached to risers which came up between the strips of wood and then laid homosote on top of the two strips of wood. You form the curves and then attach the blocks which seperate the two 1/4 inch strips. I had no trouble with the track for 20 years or so even though the basement had both temperature and humidity problems.
I would like to use spline roadbed on a model railroad. I would have to use 15" radius due to the area available. This is going to be a small logging railroad in an extra bedroom. The spline roadbed looks fantastic and I’d like to employ it on this project. This layout will also consist of 4 modules that can be separated and moved if need be. Any advice would be welcome. This forum has provided such valuable information already so I figured I’d start asking questions.
I’m using spline roadbed on my V&T Lines with a new material, called “Crystal White”. My curves are 24" radius. I’m not sure about masonite spline, however I am pretty sure that you should be able to get curves down to 15" with “Crystal White”. Here is a photo. You can also see and learn more on my WEB site. Also, this material is more expensive than other traditional materials used for spline, but it seems to be cleaner and easy to work with.