This 70,000-pound (35 tons) Caterpillar crawler Tractor is a specially constructed machine with extra-long, extra-wide tracks and winterized for operation in minus 65 degree temperatures,, Caterpillar Tractor Co., Peoria, Ill,, manufactured ten of these 155-horsepower "low-ground-pressure D8's" plus 14 other special machines for Operation Deep-freeza, Rear Admiral Richard E. Byrd's expedition to the South Pole. The machines, which have 54-inch track shoes in contrast to the customary 24-inch sho