I'm not really sure what the radius is: this area is part of a curve around one end of part of the layout room. The room is 8' wide at this end, with about 8" or 9" lost on either side for background scenery. Chippawa Creek bridge, which is mostly straight, is in the middle part of the curve, so the radius is probably about 34", although is may be a little less. Sorry that I can't be more specific, but I had a bunch of curves cut out of plywood, and I just picked the ones that fit the best. Minimum mainline radius is 30", and it's not at this curve.
Wayne