The USRA Light Santa Fe was produced in smaller numbers than its heavy sister. Compared to this, it had drivers which were six inches smaller and a cylinder diameter that was three inches smaller. It shared the firebox design and the number of boiler tubes with the 2-6-6-2 Mallet, but the combustion chamber and the tubes were shorter.
Of 94 Light Santa Fes built, 75 came from ALCO and 19 from Baldwin. The biggest operator was the Southern, which used 50 of them as class Ss-1. The Seaboard Air Line got 15, the Boston & Albany and Duluth, Missabe & Northern got ten each, the Chicago & Western Indiana five and the Ann Arbor four. 