They were originally used in the late-19th C. on theretofore, untreated telegraph poles, sleepers, trestles, timbers, outbuildings & such to record & determine which species of wood & which of the various (wood) treatments would best be resilient to wear, weathering, rot, etc...As I young boy, on vacation in north central Wisconsin, I had collected a couple of these marker nails from old crumbling ties, or out of the rock bed. I wasn’t sure what they denoted but recently looked them up. Could mean different things evidently. Age of a repair, or to monitor the condition of ties, etc., but maybe some one has a better description yet.
Thanks much!They were originally used in the late-19th C. on theretofore, untreated telegraph poles, sleepers, trestles, timbers, outbuildings & such to record & determine which species of wood & which of the various (wood) treatments would best be resilient to wear, weathering, rot, etc...