Minneapolis, St Paul & Sault Ste Marie 2-10-0 "Decapod" Locomotives in 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. (Thanks to Chris Hohl for his 6 June 2017 email noting the correct road number as delivered.) Works number was 17914 in July 1900.

This locomotive originally was built for the Buffalo & Susquehanna as their #113, 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 renumbered 950 in November 1912 and later 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 Rail Data Exchange.

Note that the superheater area in the specs is estimated. It is a calculation based on taking the diagram value of 690 sq ft (64.1 sq m) 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)
CountryUSAUSA
Whyte2-10-02-10-0
Number in Class11
Road Numbers600/950950
GaugeStdStd
Number Built1
BuilderBurnham, Williams & Coshops
Year19001924
Valve GearStephensonWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)19.33 / 5.8919.33 / 5.89
Engine Wheelbase (ft / m)28.50 / 8.6928.50 / 8.69
Ratio of driving wheelbase to overall engine wheebase 0.68 0.68
Overall Wheelbase (engine & tender) (ft / m)57.33 / 17.4757.33 / 17.47
Axle Loading (Maximum Weight per Axle) (lbs / kg)39,500 / 17,917
Weight on Drivers (lbs / kg)185,100 / 83,960190,250 / 86,296
Engine Weight (lbs / kg)210,000 / 95,255212,250 / 96,275
Tender Loaded Weight (lbs / kg)120,000 / 54,431131,550 / 59,670
Total Engine and Tender Weight (lbs / kg)330,000 / 149,686343,800 / 155,945
Tender Water Capacity (gals / ML)7000 / 26.526000 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)9 / 8.2010 / 9.10
Minimum weight of rail (calculated) (lb/yd / kg/m)62 / 3163 / 31.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)55 / 139755 / 1397
Boiler Pressure (psi / kPa)215 / 14.80180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)17" x 32" / 432x81323" x 32" / 584x813
Low Pressure Cylinders (dia x stroke) (in / mm)28" x 32" / 711x813
Tractive Effort (lbs / kg)44,904 / 20368.1447,091 / 21360.14
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.12 4.04
Heating Ability
Firebox Area (sq ft / m2)223.90 / 20.81274 / 25.46
Grate Area (sq ft / m2)37.50 / 3.4937.58 / 3.49
Evaporative Heating Surface (sq ft / m2)3018 / 280.482381 / 221.28
Superheating Surface (sq ft / m2)460 / 42.75
Combined Heating Surface (sq ft / m2)3018 / 280.482841 / 264.03
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

Photos