Hi clinchfield36: I used spline roadbed on my layout. I guess I’m old fashioned, but I like wood. I used 1/4" Luan exterior plywood for my splines. I cut them 1" wide with a circular saw, but if I were doing it again, I would cut them 3/4" wide to match the 1x4, 1x6, etc that I used for the rest of my bench work. I glued them with yellow carpenter’s glue. They are supported approx. 24" apart. I used a Surform plane to level the top. I think the only disadvantage is that they can only be bent to approx. a 28"r. and I needed lots of clamps. I nailed cork roadbed on top, but it could be used as is for roadbed. Just another option. Here’s a few pics. 
Is there any specific reason that you wish you would have gone with 3/4" thick splines vs. the 1" you used? I only ask becuase I am just about to start ripping splines to 1" and now am wondering if I should rethink this. My reasoning for going with 1" thickness is that I would have a bit more gluing surface to attach the cardboard webbing I’ll be using as my scenery base. Thanks, Jamie
Hi Jamie: Thanks for your reply. When you splice the 1" spline to any 3/4" material, you have to add a 1/4" spacer to the 3/4" material to make the bottom level. If you make the spline 3/4", the splice plate will be even on the bottom. It would just make it a little easier. I think 3/4" is fine to attach cardboard strips. If you use hot glue, It only takes a small spot to hold cardboard strips. Good luck with your layout! Please show pics of your progress.
As for turnout operation, I would be inclined to notch out the top of the spline and glue in a 3"x4" or so piece of 1/4" plywood and operating the turnout from the outer end of the throw rod with the tortoise screwed into the bottom of the plywood. That way you are not weakening the spline and the machine is easily accessible for adjustment or replacing. jc5729 John Colley, Port Townsend, WA
thanks, grampys trains… i’m actually planning to use some 22 and 20 inch curves. what width of splines should i use to achieve those tight radii?
I use masonite spline roadbed. I learned it by Joe Fugate. Take a look at my website.
Hi: I don’t think luan will bend to that tight of a radius. Although I have not tried masonite, this may be what you’d need to use. Maybe someone who uses masonite can tell you if it will bend to that raidus. Years ago, I ripped 3/4" pine boards to 1/4" thickness and made about a 22"r. curve. I just used it a couple years ago for hidden track through a tunnel.
I don’t think 6 mm thick masonite splines will bend that tight. But maybe if you use 3-4 mm masonite and more splines.
Grampys, Thanks for the additional information. I will definitely use the 3/4" splines because my flat areas will be using 3/4" thick plywood for the base. By the way, I have just posted updated pics of my layout at the bottom of this thread:
http://cs.trains.com/forums/2/1489391/ShowPost.aspx#1489391
I figure I am about a month away from starting trackwork since I have a helix [:O] and the swing gate to complete. In reality, I will probably start laying track once I have just a few turns of the helix completed so I dont get helix “burnout.” Jamie
Hi Jamie: I’m happy to be of some small help. I checked out your progress, WOW, that is truly impressive bench work. It looks to me like you’re well on your way to a great layout. Keep up the good work.
Thanks for the kind words…so far so good, soon the “technical” work ends and the “artistic” work begins! Jamie