The Nickel Plate Road was among the first railroads which ordered 4-6-4 “Hudsons”. Numbers 170 to 173 were delivered by ALCO-Brooks in 1927, followed by numbers 174 to 177 built by Lima in 1929. The Brooks locomotives were designated class L-1a and had built-up frames and a boiler pressure of 225 psi. The Lima locomotives formed class L-1b and featured cast steel beds, but boilers with only 215 psi.
They were later fitted with large smoke deflectors, but No. 177 shown in the photo was also tested with another design. After World War II they also received Timken roller bearings and thicker tires for a driver diameter of 74 instead of 73 inches. The class was replaced by diesels in the mid-fifties and today No. 170 is on display at St. Louis, Missouri.