The Soo Line owned only four 4-8-4 or Northern type locomotives, Nos. 5000-5003 of class O-20 delivered by Lima Locomotive Works in 1938. Technically owned by MStP&SSM component Wisconsin Central, these handsome engines were the Soo's heaviest freight haulers, weighing 453,500 pounds and developing 79,400 pounds of tractive effort. With cylinder dimensions of 26x32 inches, they sustained 270 pounds per square inch of boiler pressure and rolled on 75-inch disc drivers. Their grate area measured 88 square feet, their evaporative heating surface 5140 square feet, and their superheater surface 2120 square feet. All were scrapped, but the tender of one of them was paired with Grand Trunk Western 4-6-2 No. 5629 during and after its career in excursion service until that locomotive was, regrettably, scrapped in 1987. (I have not been able to determine which of the Soo's O-20 class contributed the tender.) This Lima builder's photo was scanned from the 1951 edition of World Railways.