This locomotive was part of the Santa Fe Railway's Class 3450 Hudsons. They were built in 1927 as coal burning locomotives but were later converted to burn oil in the 1930s. At the same time, their original 73" drivers were replaced with 79" drivers and the operating boiler pressure was raised to 230 PSI. These changes had the effect of increasing top speed and operating efficiency for high-speed passenger train operations. Starting tractive effort was 43,300 lbft.