The layout itself rested on small pieces of 1/4 round which were located inside the corners of the frame corners. The glass top would be placed onto a frame that was fitted to the top of each corner.
There were a number of other issues with the execution of the design. Most notable was that the wood frame was made op largely of AB-grade plywood, so the edges of the plywood were raw and unfinished. Likewise, the glass top frame would prove to be a problem, since it severely limited access to the railroad. I had planned to mount the glass-top frame with threaded metal inserts; screws would run through the wood glass frame into these inserts.
Ultimately, this design reached a dead-end, largely because of problems with access to the tracks. There also was no provision for locating the transformers and controls. I kept this layout table around for several years, trying to work through the design issues. Ultimately, moving to smaller quarters led to scrapping this idea. I recovered the expensive Z-Scale track and the woodwork went to the curb.
I sat on the coffee table idea for several years.