Minneapolis, Sault Ste Marie & Atlantic 0-4-6 Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class Y/A (Locobase 11406)

Data from Soo 3 - 1909 Classification of Locomotives and Soo 9 - 1943 Steam Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Stanley later added Soo 3-1909 Classification of Locomotives in August 2013. (Thanks to Chris Hohl for his 20 April 2020 email correcting the original WSSM&A road number, engine wheelbase, and engine weight.) Rhode Island works number was 1876.

Although clearly meant to be a switcher (and thus excluded from Locobase 3.0), this engine merited inclusion nevertheless because it was based on Matthias Forney's tank locomotive design. The permanent junction of tender and locomotive allowed for a large and generously endowed firebox.

A later boiler had ten fewer tubes, which reduced evaporative heating surface area to 925 sq ft (85.94 sq m). Delivered as a Forney, the Y's bunker and tank were later exchanged for a separate tender, creating an 0-4-0 which merited a change in class to A.

Rhode Island completed a very similar engine in the same year for the Boston & Providence; it had four more boiler tubes and a evaporative heating surface area of approximately 950 sq ft.(88.26 sq m).

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID11406
RailroadMinneapolis, Sault Ste Marie & Atlantic (Soo)
Number in Class1
Road Numbers37/320
Number Built1
BuilderRhode Island
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m) 6.50 / 1.98
Engine Wheelbase (ft / m)25.58 / 8.28
Ratio of driving wheelbase to overall engine wheelbase 0.25
Overall Wheelbase (engine & tender) (ft / m)25.58 / 8.28
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)69,190 / 31,384
Engine Weight (lbs / kg)118,500 / 31,384
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)118,500
Tender Water Capacity (gals / ML)1900 / 7.20
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)4 / 4
Minimum weight of rail (calculated) (lb/yd / kg/m)58 / 29
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)57 / 1448
Boiler Pressure (psi / kPa)160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)17" x 20" / 432x508
Tractive Effort (lbs / kg)13,791 / 6255.50
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.02
Heating Ability
Tubes (number - dia) (in / mm)162 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)10.67 / 3.25
Firebox Area (sq ft / m2)85.32 / 7.93
Grate Area (sq ft / m2)17.73 / 1.65
Evaporative Heating Surface (sq ft / m2)990 / 91.97
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)990 / 91.97
Evaporative Heating Surface/Cylinder Volume188.57
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation2837
Same as above plus superheater percentage2837
Same as above but substitute firebox area for grate area13,651
Power L14101
Power MT261.34

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