It must be those Robertson screws. [(-D]
I’m going to use 1x6 Poplar and 1/2" furniture grade Birch plywood for the new layout. And put 1/2 homasote over that for yard areas, as well as homasote roadbed under other trackage.
It will be “open grid” or “cookie cutter” in most places, so that you can get up under the scenery to some hidden trackage.
Rolling terrain scenery, typical here in the piedmont of the Appalachians, will be plaster on wire screen.
But what would I know, this is only the 6th layout in 50 years, not counting the three I helped others build.
And I already have a large supply of Phillips screws…
Sheldon