I used Homabed and Homasote for roadbed, but wanted to fill in the gaps at joints and kerf lines. I tried a few different products to fill in the gaps. I started with spackle, but found it to bee too crumbly. I moved on to a drywall type compound called Custom Patch, but it seemed to be shrinking. I finally used Elmer’s Wood Filler and it seems to do the trick. I painted over the roadbed with some latex interior house paint. I finsihed up the road bed for the Odom Lead; the head of the Industrial Lead; and the SIG Runaround Track.