"072" Sorry, no.
Assuming that you mean "What is the widest curve I can use at the end of the table to form an end loop...?" The answer is simple: The board is 48" wide. You can use up to a curve of 48" diameter, or 24" radius. Of course, you would need some room at the edge of the track, so you need to make the curve smaller. But "072" (the number denotes the diameter of the circle formed by the curved sections, in toy train nomenclature) is definitely not the answer, since that curve would be 6' across. Your track will be hanging over thin air by a foot at each side of the table. In H0, you would specify something slightly less than "36" radius" since in H0 we measure curves and circles using the radius, not the diameter.
