The platform structure in progress

I have done some cad drawings,for laser cutting, of the cross section pieces to support the platform. I have decided to simplify the structure , while still taking into account the real thickness of the platform versus the thickness of the tracks. There are 16 cross pieces that make up the underground structure below: between the extents of the middle void in plan. The intent is to have doweling already inserted in the track structure and to be used like a book shelf pin to support the cross members. The cross members are 3 layers, the middle layer with slits to accommodate the doweling and to suspend of the tracks. The middle layer also has slits at the bottom of columns and top of structure to allow a friction fit for 1/8 inch screw. To help with further development downward and to fasten the platform layer onto the model. I am still figuring out a universal connection for wall inserts within the interior.