This view of U-3-a 4-8-4 No. 6309 was taken in Sarnia, Ontario, on April 15, 1948 after this class, built originally for the Grand Trunk Western, was supplanted by the GTW's U-3-b class. Nos. 6300-6311 continued in service on eastern Canadian National lines, and I recall seeing one of them in northwestern Vermont on the line connecting with the Central Vermont at East Alburg. This view, from the collection of Ed Emery of Toronto, was provided by Tom Rock of Rock on Trains. Whether Mr. Emery was the photographer is unknown.
The dimensions of the U-3-a class were similar to those of the CNR's U-2 class except that they had 26¼x30-inch cylinders and weighed 399,000 pounds. They had 84 square feet of grate area, 4402 square feet of evaporative heating surface, and 1955 square feet of superheater surface. Apparently, due to variations in design, they put out between 59,000 and 60,200 pounds of tractive effort. No. 6309 belonged to the group that claimed the higher figure, making them the heftiest 4-8-4s built for the Canadian National system.