Maine Central Railroad steam switchers were designated Class K. They were of 0-6-0 wheel arrangement in the Whyte notation, or "C" in UIC classification.
Twenty locomotives numbered 161 through 180 were active in 1923, and worked in Maine's largest cities until replaced by diesels after World War II.
[1] Earlier K class 0-6-0s were rebuilt with higher-pressure boilers in Maine Central's Waterville shop between 1913 and 1916 as sub-classes K-6 and K-7.
These reboilered locomotives weighing 90,000 lb (40.8 tonnes) with tractive effort of 20,000 lbf (89.0 kN) were numbered 153 through 160.
World War I caused 1918 production to be split between builders numbers 57883 and 57884 from Schenectady, and 59865 and 59866 from ALCO's Pittsburgh plant.