Here's my latest try- and the first two from my last post. Lower side of the image is the front, upper is against the slope of the ceiling. HO scale, and yes those are 15" R loops. Less than ideal I know, but all my rolling stock is short (40' or less) and seem to operate fine on my mock-up. My GP-9 will push 14 cars through the loop with no problem. Which do you like?