Port Blakely Mill Company 2-8-2 "Mikado" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 1 (Locobase 13704)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 36, p. 93. Works number was 35781 in December 1910.

This was the biggest locomotive to date to run on the PBMC short line. Even at the reatively low pressure setting, the oil-burning #1 generated good power for logging trains on 40-lb/yard (20-kg/metre) rail on a profile that included 2 1/2% ruling grades and 20-degree curves. It was not quite as big, however, as the more common version operating on many logging roads in the Northwest at the same time.

By 1916, the3 engine had gone to the Stimson Lumber Company, which was bought by Weyerhaeuser in 1917. The latter renumbered this Mikado 105.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID13,704
RailroadPort Blakely Mill Company
Number in Class1
Road Numbers1
Number Built1
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)12.08 / 3.68
Engine Wheelbase (ft / m)27.25 / 8.31
Ratio of driving wheelbase to overall engine wheebase 0.44
Overall Wheelbase (engine & tender) (ft / m)48.96 / 14.92
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)110,000 / 49,895
Engine Weight (lbs / kg)136,000 / 61,689
Tender Loaded Weight (lbs / kg)60,000 / 27,216
Total Engine and Tender Weight (lbs / kg)196,000 / 88,905
Tender Water Capacity (gals / ML)3000 / 11.36
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)1500 / 5.70
Minimum weight of rail (calculated) (lb/yd / kg/m)46 / 23
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)44 / 1118
Boiler Pressure (psi / kPa)160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)18" x 24" / 457x610
Tractive Effort (lbs / kg)24,035 / 10902.11
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.58
Heating Ability
Firebox Area (sq ft / m2)140 / 13.01
Grate Area (sq ft / m2)25.50 / 2.37
Evaporative Heating Surface (sq ft / m2)1918 / 178.19
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1918 / 178.19
Evaporative Heating Surface/Cylinder Volume271.34
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4080
Same as above plus superheater percentage4080
Same as above but substitute firebox area for grate area22,400
Power L14346
Power MT348.41

All material Copyright © SteamLocomotive.com
Wes Barris