The Santa Fe was one of the first railroads to acquire the 2-8-4 or Berkshire type. However, its 4101 class that Baldwin Locomotive Works delivered in 1927 were not quite of the advanced "superpower" design pioneered by Lima Locomotive Works in 1925. This is revealed by the lower ratio of their 1246 square feet of superheater surface to 4577 square feet of evaporative heating surface (compared with 1881 and 4276, respectively, for the Lima design on the Boston & Albany). For other specifications of these AT&SF Berkshires, consult the commentary for No. 4111 following. This image of the "class engine," No. 4101, was provided by Carl Weber from his extensive collection. No information is available concerning the date, location, or photographer.