With 80-inch drivers, the ACL R-1s had cylinder dimensions of 27x30 inches and sustained 275 p.s.i. of boiler pressure. They had 4753 square feet of evaporative heating surface, 1425 square feet of superheating surface, and a grate are of nearly 98 square feet. Tipping the scales at 460,270 pounds, they mustered a tractive effort of 65,800 pounds. All driving axles had roller bearings, and the engine bed was a one-piece cast steel frame. No. 1809 of the R-1 class poses at Jacksonville on April 9, 1948 in an image from William D. Volkmer.