Norm,
Excellent progress on your layout and excellent choice of turntable. I have the 34" and it has been trouble-free since day one. I enjoy reading your updates - keep them coming!
Regarding Dennis's question:
"The reason I ask is I am designing a new layout and using atlas 099 -090 curves and am keeping a 4 1/2 inch distance between them. But I am wondering if that will be enough for engines like the scale big boy, cab forward, etc"
I used Atlas Ø108 and Ø99 for my dual main and kept them at a constant 4-1/2" spacing. With my MTH Premier Big Boy on the inner curve (Ø99), I can run almost everything I have running on the outer Ø108 curve, but just barely in some cases.
The only exception is my MTH Premier DDA40X - I cannot run it on the outer curve with the Big Boy on the inner curve. The combination of the chord the DDA40X creates is too much for the Big Boy overhang.
Alex