The Wabash class K-3 consisted of 30 locomotives which were based on the USRA Light Mikado that was designated K-2 at the Wabash, but had a firebox and tube heating surface that was nearly as big as that of the Heavy Mikado. The boiler pressure had been increased to 210 psi, but the grate and cylinders still had the same sizes.
Schenectady built 30 in 1923, of which the last five had a booster. The first 25 were only designated K-3 and numbered 2250 to 2274, while the last five with booster were designated K-3b and numbered 2275 to 2279. Later these locomotives got Worthington feed water heaters and Duplex stokers. No. 2254 had to be scrapped in 1944, but the others were only scrapped between 1950 and 1955.