Once the first spline is installed, the rest is relatively easy. I cut a large collection of plywood blocks, a sample of which are shown in the next photo. They measure 1" (2.54cm) tall, 1/2" (1.3cm) wide, and 9/16" (1.4cm) deep. When glued in place and with three splines, the total subroadbed width will be 1.5" (3.8cm).



Then, using the same method as described in the previous page, I inset the second piece of Masonite hardboard spline, which is the center piece, into the existing subroadbed and started gluing the blocks in between the two splines. The hard part here is to make the spline fit just right. As the blocks are glued, the loose spline will move around. What I did was temporarily insert some blocks at strategic locations between the installed spline and the loose one, determined where the other end of the spline would end, and cut it to length. Then I made sure that the groove cut into the plywood with the fret saw was a bit longer than needed. That allowed for some additional adjustment as the blocks are being glued in place. This method worked well.



This overhead view shows that I glued some blocks every four to five inches. The blocks with the clamps are glued and drying. The blocks without the clamps are temporary spacers.



As I am gluing the blocks on the other end, this end of the spline is allowed to flow freely.



From this vantage point you can see the completed spline subroadbed. The beauty of this method is that it provides for natural easements, which makes it easier for longer engines and cars to take the curves.