The Soo Line owned 21 4-8-2s of the light USRA design constructed in three groups. No. 4010, shown here in an undated photo at an undisclosed location, was the first of eight locomotives delivered in 1928 by the American Locomotive Company. These Mountains were the premier dual service power for the Soo Line in pre-diesel days. They had cylinder dimensions of 27x30 inches, a boiler pressure of 200 p.s.i., and a driver diameter of 69 inches. Their grate area totaled 77 square feet, their evaporative heating surface 3789 square feet, and their superheater surface 1103 square feet. Weighing in at 231,500 pounds minus tender, they developed 53,883 pounds of tractive force. The image, taken from a long-discontinued Internet site, appears also in the ABPR Archive from Bud Laws, original photographer not specified.