Probably not a good idea to Google that!
The salvaged timber used for the framework of Grande’s baseboard came with quite a bit of plasterboard attached. This stuff is horrible, you can’t recycle it and it’s virtually impossible to find a use for broken bits so they just go in the dustbin… Unless you’re a railway modeller. In that case you break up the plasterboard to make hardcore, then use it for terraforming.
Once broken up by crushing it in a Mole wrench with the jaws set just slightly narrower than the board’s thickness the bits can be packed underneath and around the unsupported sections of track.
When tamped down the rubble is coated with filler, a bit like icing a cake but without the temptation to lick the knife afterwards.
Any bits not secured by the filler will be stuck down when the ballast and other ground cover is added and drizzled with diluted PVA.
Still a lot of work to do but the gaps between the bits of scrap wood used for the trackbed are now filled in, making it look slightly more professional and a little less bodged, maybe even a bit like a narrow gauge railway with subtle differences in height between the sidings around the broad gauge interchange.
Or perhaps that’s just wishful thinking.