Erected by Canadian Locomotive Company in 1930, the Canadian National's 18 locomotives of class T-4-b were almost the last of this type to be ordered by a North American railroad. They had cylinder dimension of 24x28 inches, a boiler pressure of 275 p.s.i., and a 57-inch driving wheel diameter. Weighing 344,170 pounds, they developed a tractive effort of 61,600 pounds. They were slightly less powerful than their T-4-a predecessors of the previous year, and lacked the boosters with which the earlier class was equipped. The T-4s had a grate area of 67 square feet, 3410 square feet of evaporative heating surface, and a superheating surface of 1500 square feet. This builder's photo of the T-4-b class was scanned from the 1951 edition of World Railways.