The nine Pacifics of the class K-2 were ordered by the Western Maryland in 1912 and were much heavier than the K-1 from 1909. They had a cylinder diameter that was two inches larger and since they were superheated from the start, they had piston valves. Some had a firebox heating area of only 234 square feet and others had thermic syphons, which brought the total to 307 square feet. Like other early superheated locomotives, they had a boiler pressure of only 185 instead of the 200 psi of their predecessors. The valve gear was of the Baker-Pilliod type. As specified by the WM, many parts were interchangeable with the class H-8 Consolidations.

Later, their boiler pressure was increased to 200 psi and the valve gear was changed to the Walschaerts type. These modifications were completed by 1938. In 1947, four were converted to oil firing. They were retired between 1952 and 1954 and after that two were used to thaw the coal in hopper cars. Only 202 was preserved, but deteriorated over the years. Due to being the only remaining main line steam locomotive of the Western Maryland, it was cosmetically restored in 2008. As of the end of 2024, it seems possible that it could be restored again by the Western Maryland Scenic Railroad.