Tried playing around in Sketchup with various corrugation shapes this afternoon.  I think this is fairly close.  9” spacing as suggested by Dennis.  4.5” depth of corrugations (just a guess).  Flat on the outer surface of the end, and the space between each corrugation about 1.5” wide.  Each corrugations has a curved radius at the back about 1”.  Approx. 28 degree bend in the corrugations creates the points at each end.

Rob,

Don't take my 9" dimension as gospel; that was a late night guesstimate based on a ten foot car width... But cars of this era were narrower than ten feet, and the ends of single sheathed cars were narrower yet. Typical inside width during that period was 8'-6", or 102", plus 2 x 1.75" sheathing, 105.5", plus the two quarter inch thick flanges of the corner angles, for a total of 106" over the corners. Twelve corrugations at 9" would be 108", so they must be slightly smaller, twelve at 8.5" would be 102", leaving 4" to be divided between the center lap and corner angles; twelve at 8.25" would total 99", leaving 7" to be divided between the corner angles and center lap. I agree that the pressings are straight sided with just a small nose radius, as we are basically seeing a cross section at the rib ends, though elongated by the angle of the section plane. There will also be a small radius where the pressing meets the plane of the end, likely 1/2" or 5/8" radius, as this was good practice.

Dennis Storzek