Minneapolis, St Paul & Sault Ste Marie 2-10-0 "Decapod" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class G (Locobase 3949)

Data from "Compound Decapod - Minneapolis, St Paul & Ste Saint Marie", Railroad Gazette, Volume 32, No 25 (22 June 1900), p. 429. See also DeGolyer, Volume 23, p. 73. Works number was 17914 in July 1900.

This locomotive originally was built for the Buffalo & Susquehanna, but was returned for being too heavy for the road. Certainly Mr. EA Williams, Mechanical Superintendent of the Minneapolis, St. Paul and Sault Ste Marie, must have believed that this Vauclain compound Decapod would help him over the 165-mile Minneapolis-Pennington Division. It was to attack the ruling grade of 0.8% with a 2,000-short ton train. So he bought the orphaned B & S #113.

Although unveiled with reserved rapture in the Railroad Gazette, this engine clearly did not meet the need as it remained the only 2-10-0 the Soo ever bought. One feature was the relatively large 13" (330 mm) piston valve that served both the HP and LP cylinder on each side.

Indeed, a passing comment in "What One of the Large Locomotives is Doing," Locomotive Engineering (October 1900), p. 435 suggests that expectations fell short: "The engine was guaranteed to haul 2,000 tons up a 42-foot grade [0.8%] at 6 miles an hour. This condition has not been fully met, but the record of coal consumption is remarkably good ..."

On the other hand, the lone G endured long enough to be simpled (two 23" x 32" cylinders) and superheated; see Locobase 6767.

Class G - simpled and superheated (Locobase 6767)

Data from Soo 9 -1943 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

Note that the superheater area in the specs is estimated. It is a calculation based on taking the diagram value of 690 sq ft of "superheater equivalent" and deducting a third from it. See the logic presented in Locobase 1364.

As noted in the original G-class entry (Locobase 3949), this Decapod was the only one of its wheel arrangement to run on the Minneapolis, St. Paul & Sault Ste Marie. Perhaps because of its light axle loading, 950 survived and even endured. Along the way, the railroad simplified the power and superheated it, gracing it with 14" (356 mm) piston valves that had a 10" (254 mm) travel. In December 1924, the railroad added power reverse gear and in March 1943 they lengthened the cab.

After a long career, the Soo donated the G to the city of Ashland, Wisconsin (on the Lake Superior shore) on 16 October 1956.

Specifications by Steve Llanso of Sweat House Media
ClassGG - simpled and superheated
Locobase ID3949 6767
RailroadMinneapolis, St Paul & Sault Ste Marie (Soo)Minneapolis, St Paul & Sault Ste Marie (Soo)
Number in Class11
Road Numbers950950
Number Built1
BuilderBurnham, Williams & Coshops
Valve GearStephensonWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft)19.3319.33
Engine Wheelbase (ft)28.5028.50
Ratio of driving wheelbase to overall engine wheebase 0.68 0.68
Overall Wheelbase (engine & tender) (ft)57.3357.33
Axle Loading (Maximum Weight per Axle) (lbs)39,500
Weight on Drivers (lbs)185,100190,250
Engine Weight (lbs)210,000212,250
Tender Light Weight (lbs)120,000131,550
Total Engine and Tender Weight (lbs)330,000343,800
Tender Water Capacity (gals)70006000
Tender Fuel Capacity (oil/coal) (gals/tons)910
Minimum weight of rail (calculated) (lb/yd)6263
Geometry Relating to Tractive Effort
Driver Diameter (in)5555
Boiler Pressure (psi)215180
High Pressure Cylinders (dia x stroke) (in)17" x 32"23" x 32"
Low Pressure Cylinders (dia x stroke) (in)28" x 32"
Tractive Effort (lbs)44,90447,091
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.12 4.04
Heating Ability
Firebox Area (sq ft)223.90274
Grate Area (sq ft)37.5037.58
Evaporative Heating Surface (sq ft)30182381
Superheating Surface (sq ft)460
Combined Heating Surface (sq ft)30182841
Evaporative Heating Surface/Cylinder Volume359.00154.73
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation80636764
Same as above plus superheater percentage80637847
Same as above but substitute firebox area for grate area48,13957,211
Power L135768461
Power MT212.96490.23

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