Nation Wide Lines posted:You could always get some 5 rail standard gauge track and replace your..
72 inch radius track with the 5 rail Standard Gauge track.
...That way you could run either Standard or O gauge on the 72 inch radius loop.
72" Diameter? Radius is the "half" measurement.
72" radius 360° arc will form a 144" diameter/12 foot circle.
Better note that before you order IC GULF you might end up oversized if you order custom.
I wouldn't want the Og eclipsed by larger St.g while on the close side of the layout either. I use O between an outer loop of Super-O and an inner of 0-27 and wish constantly the tallest was the 0-27 for a stepped tier/birthday cake effect.