If you go to the Ritchie Bros auction site and check out the Williamsport, PA. auction being held on April 10, 2013 you will find many old CATERPILLAR crawler tractors. There ia a HOLT 5 TOM, a diesel SIXTY FIVE (1C29), 2 TEN's, 2 FIFTEEN's, 1 TWENTY, 1 TWENTY TWO, 1 TWENTY FIVE, 1TWENTY EIGHT, 1 THRITY, 1 diesel THRITY, 1 THRITY FIVE, 1 FORTY, 1 HIGH TEN, 1 FIFTY, 1 SIXTY, 1 SEVENTY, 1 R4, 1 RD4, 1 R5, 1 diesel FIFTY, 1 diesel SEVENTY, 3 D2's and some other CATERPILLAR tractos too. I suspect this is part of the late George Logue's collection. Just passing on this information that I stumbled onto online. Which I would win a lottery before this auction : )