Thank you all for the responses and ideas. I have access corridors around all four sides but I may have to open the middle somewhat in order to get in an access hatch.
The center section and everything labelled with height is 6 inches above the lower level tracks. And yes, I know there is probably too much track. It is one of my faults in trying to probably do too much. I was trying to design it so that I can run three trains (plus the super streets) at the same time. I'd rather run trains than create scenery but that may be major flaw on my part.
I AM concerned about the intersections from the low level to the high level and vice versa. I'll see if I can redesign that somehow. I doubt i would send a train up and down too often but your comments are well appreciated.
I did check the distance between center rails and except for the changes between levels, I seem to have at least 6 or 7 inches center rail to center rail.
Let me get back to work on the design. It seems I have plenty of time on my hands and i have to wait for the Mianne benchwork to come in anyway.
Keep safe,
John