this may help:
my way of making splined road bed.
I use luan.
it is 5 mm thick.
basically, it is 1 ply (sorta) plywood.
some people refer to it as door skin.
anyway, I use a table saw.
i set it at 1.5 inches, and rip a sheet of it all the way down.
(rip means to cut long ways) so I end up with a stack of strips 1.5 inches wide and 8 feet long.
ripping strips could also be done with a hand held circular saw.
use a cutting guide for the saw to run against and re set it every cut.
personally I think a table saw is the best way.
after I have a stack of strips, I then cut a few of them up into 1.5 X1.5 pieces.
once I have a paint can full of those, I start making the road bed.
first I establish where I want the road bed.
then I cut a few more strips into whatever length they need to be to make risers that go from the grid work up to the height of the splines.
so now, I have a single strip of luan at elevation and whatever course I want the track to take. winding, straight, curved whatever.
I attach the single strip to the riser with glue and clamps.
next I use glue and clamps and I put a spacer from the paint can every so often. then after that dries, or dry enough to mess with, I attach another 8' strip. then another series of spacers. then a full length strip. and repeat that till I have the width I want.
a sheet of luan (here) is less that 15 dollars.
I can make quite a bit of roadbed from 1 sheet of it.
(i have been known to use my air nailer to put small brads in and or staples, but, you don't really have to)
I want to add this:
I do not hand lay track any more.
I use flex track.
my method, makes it difficult to hand lay track due to the voids between the strips and so on.
if you want to hand lay track, with my spline and spacer method, you could lay a piece of the same luan flat down on top of the splines and hand lay track into that.
as for ballast:
I use wide masking tape and cover the splines.
the ballast does not fall through the tape.
anyway, that's how I do it.
I hope this helps.
How do you accurately cut these narrow strips from plywood? I have used a straightedge guide. This must be clamped on to the 4x8 sheet and is slow to use. I have tried edge guides that are attached to the circular saw base, but the edges of the cut are not exactly perfect. Is this how you do it? Also, is there any particular way to cut those nice curved ply roadbed sections? Isn't a lot of plywood wasted between the curves? What particular plywood grade is best? A lot of typical 1/2" 4-ply has voids. Thanks -- John Hutnick