Boston & Albany Pacific No. 559 appears at West Springfield, Massachusetts in September 1948, just seven months before being retired. Carl Weber provided the photo, original lensman not specified. American Locomotive Company's Schenectady Works erected the six engines of class KL in 1912. They had a grate area of 50 square feet, 2927 square feet of evaporative heating surface, and 615 square feet of superheating surface. Other specifications were identical to those of No. 581 following.