Said to be the heaviest and most powerful group of 2-8-2s, the Great Northern's class O-8 rebuilds of 1944 through 1946 presented a formidable enough appearance with their air pump-cluttered front ends and Belpaire firebox. These oil-burners, which the GN had originally constructed in 1932, put out 77,264 pounds of tractive effort and weighed 367,000 pounds. With roller bearings on all axles, they had 69-inch drivers, cylinders of 28x32 inches, and 250 p.s.i. of boiler pressure. Their grate area was 98 square feet, their total evaporative heating surface was 4726 square feet, and their superheating surface totaled 2110 square feet. These specifications, and this image of Mikado No. 3388, come from the 1951 edition of World Railways.