Class 3100 (Locobase 5442)

Data from AT&SF 7 -1920 locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive collection. Information about how many, when, and by whom this class was supplied from http://atsf.railfan.net/atsfstea.html (also visited 6 Feb 2006), the Santa Fe All-Time Steam Roster maintained by Evan Werkema. Also data from table in May 1916 issue of Railway Mechanical Engineer (RME).

Among the first of the Atchison, Topeka & Santa Fe Mikados, these were free-steamers by the looks of the numbers. In terms of weight, the Santa Fe engines were about at the median for US 2-8-2s of the pre-USRA era. Part of the firebox heating surface included 4 arch tubes comprising 25.4 sq ft.

Class 3129 (Locobase 5498)

Data from http://www.railroadingonline.com/railroads/atsf/drawings.(11 April 2003).

Data also from AT&SF 7 -1920 locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive collection. Information about how many, when, and by whom this class was supplied from http://atsf.railfan.net/atsfstea.html (also visited 6 Feb 2006), the Santa Fe All-Time Steam Roster maintained by Evan Werkema.

Similar to the 3100 class that immediately preceded them, these 30 Mikes were delivered with 57" drivers. The 200-psi boiler increased pulling power. Like the 3100s, these engines saw out steam, retiring in 1948-1954.

Class 3160 (Locobase 5499)

Data from http://www.railroadingonline.com/railroads/atsf/drawings.(11 April 2003).

3160-3187 had Baker gear; 3188-3257 had Walschaerts. As the data shows, these Mikes were considerable larger than the 3129s that immediately preceded them. If, as Drury (1993) notes, the 3129s were akin to the USRA's light Mikados, then these were the Heavies. They came in two subclasses -- the last 30 apparently being strictly coal burners while the first 98 were a mixture of coal- and oil-burning engines.

No matter, the class was big in both senses and performed throughout the system until 1950-1956. Also, the Santa Fe was sufficiently pleased with the design to go back to Baldwin for 101 more after the USRA era ended; see Locobase 2.

Class 4000 (Locobase 2)

Built 1921-1926; retired in 1950-1956.

Boiler had feedwater heater

Looks to have been based on the USRA Mikado design, but according to Wes Barris --http://www.steamlocomotive.com/mikado/atsf.shtml, accessed 21 June 2006 -- these were repeats of the 1917 3160 class (Locobase 5499). And in fact the design had the same firebox and only minor tweaks to the heating surface, which increased the superheat percentage.

Class 885 (Locobase 8249)

Data from AT&SF 7 -1920 locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive collection. Information about how many, when, and by whom this class was supplied from http://atsf.railfan.net/atsfstea.html (also visited 6 Feb 2006), the Santa Fe All-Time Steam Roster maintained by Evan Werkema.

At the same time Baldwin constructed the first-ever 2-10-2s for any railroad (Locobase 463), the builder produced these very similar Vauclain 4-cylinder compound designs, but ones in which the high-pressure cylinders lay inside of the frame and the low-pressure cylinders outside.

Confusion sets in when one looks at the 1901 diagram, which shows this class as 900-914; obviously the 1902 renumbering must have taken care of that and made room for the class 900 Santa Fes. Locobase doesn't know which way the emulation flowed, but notes that these Mikes (which were early examples of that arrangement as well) had more tubes stuffed into the same boiler barrel and consequently more heating surface.

Such a big engine couldn't be left a compound. Moreover, it needed superheat. So some time later the Santa Fe simpled and superheated this class; see Locobase 8250.

Class 885 - superheated (Locobase 8250)

Data from AT&SF 7 -1920 locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive collection. Information about how many, when, and by whom this class was supplied from http://atsf.railfan.net/atsfstea.html (also visited 6 Feb 2006), the Santa Fe All-Time Steam Roster maintained by Evan Werkema.

Locobase 8249 described the 885s in their saturated, compound-working original state. It wasn't too long before the Santa Fe was simplifying the layout and not too long after that they installed a superheater. It's odd that so packed a boiler would yield 230 small tubes to allow for 40 large ones, but the total loss in heating surface wasn't extreme.