Weyerhaeuser Timber 2-6-6-2 Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 105 (Locobase 4066)

Data from http://loggingmallets.railfan.net/, supplemented by DeGolyer, Vol 80, pp. 216+ and 228+. See Locobase 3643 for a discussion of the split-saddle tank design. Works numbers were 60784-60785 in April 1929 and 61355 in May 1930.

Two Prairie Mallet split-saddle tanks based on the compound tank delivered a year earlier (Locobase 3643), but with four HP cylinders, each receiving steam through an 8" (203 mm) piston valve arranged for 70% maximum cut off.. They were followed immediately by a similar engine with a larger boiler and grate (Locobase 4041), then a year later by a repeat of the design shown here, but with slightly higher adhesion and engine weights.

All were expected to handle 4% grades, 40-degree curves, and 60 lb/yard (30 kg/metre) rail.

All three operated for Weyerhaeuser until the 1950s, after which they were scrapped.

Class 110/1 (Locobase 3643)

Data from Jon Davis's http://loggingmallets.railfan.net/, supplemented by DeGolyer, Volume 80, pp. 334+. (Thanks to Chris Hohl for his 27 July 2015 email highlighting data from the DeGolyer specs that Locobase had overlooked.) Works number was 60561 in July 1928.

A Prairie Mallet "semi-saddle"(or split) tank, this engine worked logging lines for years, later joined by a slightly larger, younger sister, for which see Locobase 4054. Like the other Baldwin Mallet tanks, this compound used 8" (203 mm) piston valves on the HP cylinders, 12" (306 mm) on the LPs.

Davis shows that this Prairie Mallet Tank operated for Weyerhaeuser from 1928 to 1954 first from Longview, Wash., then from 1937 out of Vail, Wash. Rayonier, Inc of Railroad Camp, Wash., then ran the locomotive as a tender engine until 1968. After years of storage, enthusiasts at the Black Hills Central began restoring 110 in 1999. Its first revenue run came on 12 May 2001.

www.rypn.org/Articles/010901BlackHills has an extended article on the 110's history. Created specifically to serve logging roads, the split-saddle tank Mallet handled the rough track and steep (4-8%) grades as well as a Shay, but was easier to maintain. And so flexible was the layout that 40-deg curves [146 foot/44.5 kg/metre radii] were well within the engine's turning radius. The Baldwin logging engines were a big hit with their crews because they were "clean" engines (oil-fired and superheated), unlike the older engines that threw water, soot and "other gunk" out of the stack.

Class 110/2 (Locobase 4064)

Source of information is an account by William Schneider for the PSMRA presented by the SDRM's website. See also http://loggingmallets.railfan.net . See also DeGolyer, Vol 80, pp. 340+ and 348+. See Locobase 3643 for a discussion of the split-saddle tank design. Works numbers were 62064-62065, 62068 in 1937 (62064 in June).

These unusual locomotives worked the Washington State forest logging lines for years until 1967. As built the Prairie Mallet articulated design featured split saddletanks on the boiler (one over each engine unit), which shortened the engine's wheelbase. The specifications describe the engines as "in general to be duplicates as Clemons Logging Company's Locomotive No 8, Baldwin class 16 30/50 1/4 DD 6 [Locobase 4052], except where otherwise specified and to embody modern Mallet construction."

Eight-inch (203 mm) piston valves admitted steam to the HP cylinders, 12" (305 mm) piston valves served the LPs.

After stints with Weyerhaeuser (1937-1946) and Rayonier (1946-1967), Georgia-Pacific bought #110 for the California Western. The CW converted it to a tender engine, removing the distinctive tanks and fuel bunkers in the process. In 1984, runs on the Super Skunk tourist service came to end and CW #40 was donated to the Pacific Southwest Railway Museum Association, later passing on to the San Diego Railroad Museum.

Class 111 (Locobase 4041)

Data from http://loggingmallets.railfan.net/, supplemented by DeGolyer, Vol 80, pp. 222+ . See Locobase 3643 for a discussion of the split-saddle tank design. (Thanks to Chris Hohl for his 9 May 2015 email catching a ridiculously low adhesion weight because of a dropped zero in the entry.) Works number was 60811 in May 1929.

Weyerhaeuser clearly was sampling different variations of simple and compound-expansion split-saddle-tank articulated locomotives. Baldwin had produced two simple-expansion engines the previous month with boilers that would also appear in two different Mallet-compound tank variants. The 111 was bigger and had an all-simple expansion cylinder setup with each cylinder taking steam through 8" (203 mm) piston valves that were set for a 70% maximum cutoff.

Jon Davis of loggingmallets notes that this burly little split saddle tank ran for Weyerhaeuser until 1947 at three different locations. It then travelled north to Vancouver Island, BC, for Canadian Forest Products, where it operated until 1962. It was then scrapped.

Class 4 (Locobase 3166)

Data from http://loggingmallets.railfan.net/list/list.htm and DeGolyer, Vol 80, pp. 356+. See also "LoggerHogger", a member of a TrainOrders.com forum who posted "Sierra #38 & Rayonier #120 - Weyerhaeuser's Twins!" on 9 January 2009 at 0700 (http://www.trainorders.com/discussion/read.php?10,1844966, last accessed 2 July 2012). Works numbers were 61781 in September 1934 and 61904 in 1936.

Baldwin's specification book Volume 80 describes #4 beginning on page 356 and #120 on page 364.

Clearly, Weyerhaeuser wanted to put as much adhesive weight on 66 1/2 lb/yard (33.25 kg/metre) rail as it could manage. These behemoths didn't delve deeply into the timberlands, instead negotiating curves of a relatively modest 18 degrees (320 foot/97.5 metre radii) and grades that maxed out at 2%. Their HP cylinders took steam through 10" (254 mm) piston valves while the LP cylinders used 12" (305 mm) piston valves.

120, which was ordered a little later (order 16 36/56 1/4 DD 54) is described in the specs as a "duplicate of 16 36/56 1/4 DD 53 except where otherwise specified."

LoggerHogger explains that though both engines were indeed sister engines in WT, they did not work on the same line until the mid-1950s. 4 went to work on the West Side line running out of Klamath Falls, Oregon. Her massive bulk and size didn't suit the track and she suffered several derailments. It was only in 1952, however, that the 4 went to the Sierra Railroad as their 38. Sierra sold the 38 to Rayonier Company in August 1955 where the engine ran until 1967 when it was retired and put on display. 4 has since been moved twice, the second time to Merritt, Ore.

120's first service ran out of Vail, Wash. Later, WT's Chehalis Western used her to take logs to the Milwaukee Road junction. 120's reunion with 4 came in 1954 when Rayonier bought the former engine. Its career came to a premature end in 1962 when the crown sheet failed after the boiler's water level fell too low. Repairs would have been costly, so the engine was scrapped and the tender salvaged as a water car.

Specifications by Steve Llanso of Sweat House Media
Locobase ID4066 3643 4064 4041 3166
RailroadWeyerhaeuser TimberWeyerhaeuser TimberWeyerhaeuser TimberWeyerhaeuser TimberWeyerhaeuser Timber
Number in Class21312
Road Numbers105-107110/1110/2, 112, 91114, 120
Number Built21312
Valve GearWalschaertWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft)88889
Engine Wheelbase (ft)37.7523.6737.9237.7541.33
Ratio of driving wheelbase to overall engine wheebase 0.21 0.34 0.21 0.21 0.22
Overall Wheelbase (engine & tender) (ft)37.7537.7537.9237.7569.67
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)208,000183,000210,000220,000252,600
Engine Weight (lbs)246,000222,000247,000264,000293,000
Tender Loaded Weight (lbs)143,000
Total Engine and Tender Weight (lbs)246,000222,000247,000264,000436,000
Tender Water Capacity (gals)3200250032007000
Tender Fuel Capacity (oil/coal) (gals/tons)12001200120012002500
Minimum weight of rail (calculated) (lb/yd)5851586170
Geometry Relating to Tractive Effort
Driver Diameter (in)4444444451
Boiler Pressure (psi)200200200210225
High Pressure Cylinders (dia x stroke) (in)16" x 24" (4)17" x 24"18" x 24"16" x 24" (4)20" x 28"
Low Pressure Cylinders (dia x stroke) (in)26" x 24"28" x 24"31" x 28"
Tractive Effort (lbs)47,47637,54542,51749,85059,312
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.38 4.87 4.94 4.41 4.26
Heating Ability
Firebox Area (sq ft)128128128142198
Grate Area (sq ft)26.2026.2026.2041.5057.30
Evaporative Heating Surface (sq ft)16541654165423003113
Superheating Surface (sq ft)358358358583895
Combined Heating Surface (sq ft)20122012201228834008
Evaporative Heating Surface/Cylinder Volume148.07262.33233.99205.91305.76
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation524052405240871512,893
Same as above plus superheater percentage61836183618310,45815,729
Same as above but substitute firebox area for grate area30,20830,20830,20835,78454,351
Power L172435486473011,3849506
Power MT460.62396.54297.94684.47497.79


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