Pittsburgh & Shawmut / Portland & Southwestern 2-8-2 "Mikado" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class 17 (Locobase 15209)

Data from DeGolyer, Vol 71, pp.141+. Works number was 57201 in September 1923.

Compare this straightforward oil-burning Mikado to P&SW's much more unusual 2-6-6-2 Mallet (Locobase 4059) and notice how close the weights, heating surface, and grate areas are to each other. In 1910, the P&SW adopted an exotic layout that remained unchanged for as long as the engine remained in service with successor roads.

The 17 was sold to Clark & Wilson Lumber in Goble, Ore, from which it was sold in 1947 to the Valley & Siletz. Under that herald, the 17 operated another decade before being scrapped in 1957.


Class 6 (Locobase 15484)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Vol 80, pp. 156+. Works number was 58419 in May 1925.

Using a standard superheated logging Mikado design, Baldwin would fulfill orders for side tanks, such as the present #6 ordered by the Clark & Wilson Lumber Company, or saddle tanks. The 6 operated on rails weighing 56 or 60 lb/yard (28 or 30 kg/metre) that ran over a profile that had tight 35 degree curves and precipitous 9% grades. Like the other tanks, the 6 used 8" (203 mm) piston valves.


Class J/J-1 (Locobase 14093)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University , Volume 47, p. 56. Works numbers were 40589-40592, 40612-40617 in September 1913 and 212-217 in August 1914.

The Shawmut Line was a subsidiary of the Pittsburg, Shawmut & Northern. According to the PS & N Railroad History site (http://www.psnrrhs.org/psnrrabout.html, last accessed 29 April 2012), the new line, which was based in Brookville, Pa and was physically separate from the PS&N, was built as the Brookville & Mahoning. To avoid confusion with the Boston & Maine, the new railroad was renamed P & S. (Note that this was the Pittsburgh, not the Pittsburg as in the PS&N). The PS&N leased the P&S from 1906-1916, when the latter road ended the lease. During that period, the Shawmut Line acquired these ten Mikados, which had large saturated boilers.

The history site says that the P&S was always the more (or only) profitable part of the PS&N and after its separation, the PS&N died a lingering death. On the other hand, says the site "Although the Shawmut was not prosperous, it had its halcyon days, and despite bankruptcy, new tracks were laid to handle increasing mountains of coal, and a fleet of modern steam locomotives with the Shawmut trademark burnished the rails for nearly 50 years."

Two of the class--205, 211--were scrapped in 1938, but the others all served through World War II with the 203 being scrapped in December 1948 and 214-215 and 217 being scrapped in December 1953.

Specifications by Steve Llanso of Sweat House Media
Class176J/J-1
Locobase ID15,209 15,484 14,093
RailroadPortland & SouthwesternPortland & SouthwesternPittsburgh & Shawmut
CountryUSAUSAUSA
Whyte2-8-22-8-2T2-8-2
Number in Class1116
Road Numbers176202-217
GaugeStdStdStd
Number Built1116
BuilderBaldwinBaldwinBaldwin
Year192319251913
Valve GearWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.08 / 3.9911.50 / 3.5114.50 / 4.42
Engine Wheelbase (ft / m)27.08 / 8.2525.92 / 7.9032.33 / 9.85
Ratio of driving wheelbase to overall engine wheebase 0.48 0.44 0.45
Overall Wheelbase (engine & tender) (ft / m)55.44 / 16.9025.92 / 7.9062.33 / 19
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)141,000 / 63,957130,000 / 58,967181,000 / 82,100
Engine Weight (lbs / kg)179,000 / 81,193169,000 / 76,657228,000 / 103,419
Tender Loaded Weight (lbs / kg)99,000 / 44,906130,000 / 58,967
Total Engine and Tender Weight (lbs / kg)278,000 / 126,099169,000358,000 / 162,386
Tender Water Capacity (gals / ML)4500 / 17.052000 / 7.587000 / 26.52
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)2000 / 7.60800 / 314 / 12.70
Minimum weight of rail (calculated) (lb/yd)595475
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)48 / 121942 / 106751 / 1295
Boiler Pressure (psi / kPa)180 / 12.40185 / 12.80200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)20.5" x 28" / 521x71118" x 24" / 457x61022" x 28" / 559x711
Tractive Effort (lbs / kg)37,507 / 17012.9129,114 / 13205.9045,173 / 20490.15
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.76 4.47 4.01
Heating Ability
Firebox Area (sq ft / m2)154 / 14.31100 / 9.29190 / 17.65
Grate Area (sq ft / m2)41.30 / 3.8427.70 / 2.5757 / 5.30
Evaporative Heating Surface (sq ft / m2)2476 / 230.031156 / 107.403656 / 339.65
Superheating Surface (sq ft / m2)553 / 51.37242 / 22.48
Combined Heating Surface (sq ft / m2)3029 / 281.401398 / 129.883656 / 339.65
Evaporative Heating Surface/Cylinder Volume231.48163.54296.77
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation7434512511,400
Same as above plus superheater percentage8772599611,400
Same as above but substitute firebox area for grate area32,71021,64538,000
Power L111,07070246356
Power MT692.34476.47309.67