Class 4 (Locobase 14258) 
Data from http://loggingmallets.railfan.net, supplemented by DeGolyer, Vol 71, pp. 249+. Works number was 56738 in July 1923.
One of the first of 30 or so Baldwin articulated-tank logging locomotives, this engine had rectangular tanks.
After operating in Hammond's Mill City, Ore area for ten years, the 4 was sold to Mill City Manufacturing Logging Company in 1934. Mill City sold the 4 to Flora Logging, Flora to Consolidated Timber Company of Williams, Ariz. Consolidated to Saginaw & Manistee. The S&M removed the tanks and added a slope-back tender, later substituting a rectangular tender. Finally, the S&M sold the 4 to the Southwest Lumber Mills Co, where it ran for years before being scrapped in 1957.
Hammond would return to Baldwin for a two more engines in 1925 that had split saddle tanks; see Locobase 4054.
Class 5 (Locobase 4054)
Data from http://loggingmallets.railfan.net . See also DeGolyer, Vol 80, pp. 272+, and Alfred Bruce (1952). Additional data from the Arizona Historical Society's History of the Pioneer Museum found (18 April 2003) at http://www.infomagic.net/~ahsnad/LocomotiveHistory.htm . They note that the 1929 price was $46,000. Works numbers were 60871, 60870 (as numbered on the road) in June 1929.
Built as a pair, these had split saddletanks on the boiler (one over each engine unit), which shortened the engine's wheelbase, like many other logging Mallets. #6 went into service at Foss, Ore while 5 operated at Mill City. Maximum grades were given as 5.5% combined with 30 degree uncompensated curves. The firebox crown sheet was to be sloped for 8% grades, that is: "Fire box crown sheet and tubes at front tube sheet to be arranged to be covered with water for operation over grades of 8%."
#5 had the shorter career, parallelling that of #6 for the first 8 years on the Hammond Lumber and Hammon & Little River Railroad. In 1937, #5 went to Crown Willamette as their #16 and soldiered on until 1959, when she was scrapped.
#6 wandered throughout the west, winding up in Flagstaff, Arizona in 1960. She subsequently went on display in two different locations.
Data from