The 70 members of the Boston & Maine P-2 class, known as the "Minuteman Pacifics," were the railroad's most numerous group of 4-6-2 type engines and the workhorse of the railroad's passenger fleet. Coming from American Locomotive Company's Schenectady works between 1911 and 1916 (see the llustration below from a 1913 Alco sales bulletin) in several subclasses, the P-2s weighed 249,350 pounds minus tender and mustered a tractive effort of 31,560 pounds. Their driver diameter was 73 inches and boiler pressure 200 p.s.i., and their cylinder dimensions were 22x28 inches. For other dimensions consult the commentary for No. 3665 following. Carl Weber provided this view of No. 3622 which an unnamed photographer captured at Boston on March 13, 1950. Available information is inconclusive as to which P-2 subclass she belonged.