Thanks, Stewart. I have to admit I have no idea about the ruling grade, since really don't know anything about the physical characteristics of the railroad, but I'd love to try to locate it someday. The Adirondacks are a beautiful region, and there's a lot of railroad history there, particularly in the form of weird insular operations like the Fulton Chain RR and the Marion River Carry RR (built by W. W. Durant, the son of Thomas Durant of the Union Pacific RR) , as well as the narrow gauge Crown Point Iron Co. RR. Michael Kudish's map-heavy book on Adirondack railroads, "Where Did the Tracks Go" (which I highly recommend!) shows the location of the Fulton Chain RR ROW going west from Minnehaha, so it's just a matter of going up there and finding it.
-Philip Marshall