At one time the Boston & Maine owned 140 2-6-0 (Mogul type) locomotives of class B-15, some of which survived to the end of steam on the B&M in Boston suburban service. No. 1397 of class B-15b is shown here at Boston on June 7, 1939 in a postcard view attributed to David Holway. She belonged to the first group of this class, delivered by the Manchester Locomotive Works between 1903 and 1906. Although originally equipped with slide valves, beginning around 1920 many were later retrofitted with piston valves (retaining the squared steam chest) which allowed them also to be superheated. They had 19x26-inch cylinders, a boiler pressure of 200 p.s.i., and a driving wheel diameter of 63 inches. For other dimensions, consult the page for No. 1425 following.