Alameda & San Joaquin / Western Pacific 4-6-0 "Ten-wheeler" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class TF-17 (Locobase 7618)

Data from WP 2 - 1946 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also the article by Patrick Patterson," Alameda San Joaquin [sic] from Tesla to Stockton," at and the Western Pacific Online history of the A&SJ at . Works numbers were 2543-2544.

The Corral Hollow Road was built in 1895-1896 as a coal road between Stockton, Calif, and Tesla. The 36-mile (58-km) road used 56 lb/yard (28 kg/metre) rail on "closely spaced" ties. It was expected to tap coal deposits in Corral Hollow Valley. Once the promise of coal-generated power was eclipsed by the abundant hydro-electric potential, the developers turned to promoting briquetting, says Patterson, which was the packaging of coal for home heating and cooling. "They were the first to promote this process in the United States and grew to become the largest mining operation in California."Tesla Mining was an active entrepreneurial business, developing both a brick and pottery business as well as the only factory making glass panes west of the Mississippi.

The Western Pacific bought the A&SJ in July 1903 and maintained the coal business through several fires in the Tesla Mine until a flood closed the mine in 1910. Ultimately, the WP incorporated the Stockton-Tracy segment into its mainline.

"TF" stands for Ten-wheeler freight and this pair obviously delivered useful power on light branch lines . 121 was scrapped in December 1934, but 122 last ran in December 1947.

Class TP-29 (Locobase 2813)

Data from . The first 16 of the class came to the WP in 1908, having been built for two unit prices and two batches. The first batch comprised works# 45677-45682 and 45688-45689 at $13,247 each and 45690-45696 costing $14,397 apiece. The eagle eye will have spotted the disparate discontinuities in the break between batches and the raise in price.

The next year completed the class with 21 more engines. Road numbers 99-106 came first, costing $14,291 each and consisting of works# 46430-46437. Immediately following - at a higher price of $14,585 apiece - were works# 46438-46450.

Class TP-29 - superheated (Locobase 7625)

Data from WP 2 - 1946 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Firebox heating surface included 35 sq ft of thermic syphon. These were the superheated updates of the numerous 71 class, for which see Locobase 2813.

Drury (1993) notes that the WP never had a great need for heavy passenger power. So these Ten-wheelers, although "not state-of-the-art passenger power," were adequate for the road until the 1930s. While the 30s saw most of the class heading to the scrapyard, some held on through World War II. 71, 76, 77, 78, 81, 83, 84, 86, 89, 99, & 106 were last used in the late 1940s, while 94 operated until April 1953.

Specifications by Steve Llanso of Sweat House Media
ClassTF-17TP-29TP-29 - superheated
Locobase ID7618 2813 7625
RailroadAlameda & San Joaquin (WP)Western Pacific (WP)Western Pacific (WP)
Number in Class23636
Road Numbers121-12271-10671-106
Number Built23636
Valve GearStephensonWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase13.17'13.50'13.50'
Engine Wheelbase21.17'24.33'24.33'
Ratio of driving wheelbase to overall engine wheebase 0.62 0.55 0.55
Overall Wheelbase (engine & tender)46.33'57.92'57.92'
Axle Loading (Maximum Weight per Axle)45000 lbs
Weight on Drivers82500 lbs135000 lbs135000 lbs
Engine Weight114500 lbs181000 lbs181000 lbs
Tender Light Weight76000 lbs127460 lbs132000 lbs
Total Engine and Tender Weight190500 lbs308460 lbs313000 lbs
Tender Water Capacity4000 gals6000 gals7000 gals
Tender Fuel Capacity (oil/coal)1584 gals3070 gals3019 gals
Minimum weight of rail (calculated)46 lb/yard75 lb/yard75 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter57"67"67"
Boiler Pressure150 psi200 psi200 psi
Cylinders (dia x stroke)18" x 24"21" x 26"21" x 26"
Tractive Effort17394 lbs29093 lbs29093 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.74 4.64 4.64
Heating Ability
Firebox Area131 sq. ft193 sq. ft228 sq. ft
Grate Area25.68 sq. ft33.50 sq. ft33.60 sq. ft
Evaporative Heating Surface1659 sq. ft2597 sq. ft2245 sq. ft
Superheating Surface568 sq. ft
Combined Heating Surface1659 sq. ft2597 sq. ft2813 sq. ft
Evaporative Heating Surface/Cylinder Volume234.70249.16215.39
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation385267006720
Same as above plus superheater percentage385267008064
Same as above but substitute firebox area for grate area196503860054720
Power L14665763218207
Power MT373.98373.90891.99


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