spline roadbed

[Colorado Fuel & Iron RR]

I'm constructing an N scale layout using spline roadbed. The plan and benchwork, after 18 months, is completed. The splines will be made up with 1/4 by 3/4 strips of clear pine. I've been planning on laminating 4 of these together to make the roadbed. 1 inch wide, by 3/4 thick. I'm a retired trim carpenter and have done many curved staircase handrails before, same principle so I'm comfortable with the construction. Looking for a few pointers, before I dive in, I was moving through youtube too see what came up. In one of the videos the modeller highly suggested 6 strips, 1 1/2 inch wide. He said better stability would be achieved. I should mention that I will be hand laying the track. So any suggestions, past experiences, engineering suggestions, would be appreciated. So depending, the roadbed could be 1', 1 1/4, or 1 1/2. What does anyone think?
Thank you,
Rick

 

[2Tracks]

Unfortunately, I did neither N or splined roadbeds. Have you done a web or you tube search for splined roadbeds? I've seen articles on them, but it has been a while ago.......

 

[Colorado Fuel & Iron RR]

Thank you.

 

[Michael B]

There are other ways...

 

[Colorado Fuel & Iron RR]

thank you, that looks really interesting

 

[Selector]

FWIW, I have only made one layout with splined roadbed. I am not handy by any means, a bit of a klutz, but I managed to generate a very successful mainline with passing sidings.

Just so you know of my experience and technique: (this was HO)

a. 1/4" MDF 4X8 sheet cut into many 3/4" strips;
b. I did laminate three layers at a time, one against a brad forced into the middle of each spline, glued first, and clamped;
c. Make darn good 'n sure your curves, where you form them, conform closely with your track plan;
d. When those three had cured, another three, this time clamped to the ones extant;
e. 3/4" MDF in six-ply is very rigid. I bet you can go with half as many splines for your scale and still have plenty of rigidity;
f. The inherent rigidity doesn't allow you to make risers to support the splines five or six feet apart, but three feet is quite reasonable, maybe even four when ya gotta'
g. Do take a surform file and scrub both the beaded and welled glue off the bearing surface, but also to help to smooth that surface transversely. You should not have to do anything about the longitudinal axis as splined roadbed is astoundingly good out of the block that way. If you got your riser height pretty close, that is.

h. I think the idea for most applications is to drill a small hole into the middle of the splines, carefully so they don't separate, and then insert a small screw that can be countersunk a bit to not interfere with the track ties above them. The screw needs to be embedded in the splines when countersunk. Just a secure anchoring there.

It's one of those satisfying experiences that, if you go slow at first and learn what you must do to get the roadbed geometry you need for your track plan, it should turn out very well.

I have no experience to speak of with wood, so I cannot say MDF is a better product for this. I suspect it is not, and that you know better. Again, take your time, get lots of small clamps handy, do six-foot lengths all at once, half glued and set, then the next ones (but N scale should only need three laminated...?), and when you have closed the loop, start treating the surface to get it smooth across the laminates, and your flex track should flow.

 

[Colorado Fuel & Iron RR]

Thank you for your very complete study of spline construction. I started the project. Your right, the first two splines are daunting, but it becomes quite enjoyable, from there on out. Clamps are key, many and strong. You have a great looking layout. I see in yours, what I hope to see in mine, someday.

 

[Iron Horseman]

Hmmm, I just read this much closer. I have to say, I've only seen / made the spline with vertical strips with wood blocks between it, where the objective was to save weight and reduce the amount of material used, and therefore cost. I think I would have called this laminated sub-roadbed.
Interesting.

 

[Selector]

When I was researching this 20 years ago, images showed it both ways. I can see that you might get more track length if blocks are used, although my calculation showed me that I could 'laminate fully with the proceeds from one 4X8 sheet of 1/4" MDF ripped long and 11/16" wide. I ended up with 26' of single main.

 

[ShadowNix]

I used MDF and I think 8 layers... pics are below (sorry painted on some - I should have documented better ) I did like Iron said - you can skip some (see the gaps in mine) but it really becomes fun - the sanding, not so much, ahhahaha. The curves are so beautiful, especially with the natural spirals in you get. The last one shows how it looks when latex sealed with roadbed and track on it. Well, enjoy - not easy, but most good things in life aren't.

 

[Dabro67]

Long time lurker, first time poster. It's interesting that everyone has their own ideas about how to do this. I came up witjh my own version stealing a few good ideas from various sources. I'm old school so I wanted to use homosote as a track base. I used a sandwich of three strips of 1/2" homosote 1 1/4" wide with 2 strips of 3/16" masonite 1 3/16" wide. I cut a shoulder on the outside homosote strips with a router table, gave me a nice track profile. Laminated hom-mas-hom-mas-hom which gave me a 1 1/4" vertical by 1 3/4 wide spline. The top surface of the masonite strips were slightly below the homosote top. Ideally only the homosote touched the track. I didn't relish the idea of dealing with glue, so I screwd the spline together with drywall screws every 4 inches. This gave a really rigid spline that could be changed if you need to, mine span 24" between supports just fine. Then I could use track nails to seat the track, the splines could be screwed directly to the supports. Turnout areas required some custom fine work so I glued the spline together at the turnouts. Some final finishing of the top of the spline is required to get the surface leveled or super-elevated, ready for track. One thing that I discovered later in my project was using a product I had on hand called "Guardz" which is a sealer that kind of set the splines and made sanding them to final shape a bit better. Hopefully this makes some sense, I like this method, it goes fast and some of my layout now is three years old and no problems. Dave
BTW, I use undermount servo turnout actuators screwed directly to the spline, works great.