An unidentified photographer recorded this left-side view of Boston & Maine 4-6-2 No. 3630 in Boston on April 9, 1954. It reveals the Worthington type 3BL side-mounted feedwater heater that was applied to some of the P-2 class Pacifics instead of the Elesco front-mounted bundle type. The P-2 class was divided into subclasses "a" through "d," but information about the breakdown of the various subclasses is difficult to locate; it does not appear to be numerically consecutive. Carl Weber contributed the image from his collection.