Duluth & Iron Range 4-8-0 "Mastodon" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class J (Locobase 8534)

Data from M Grille & MH Falconnette, Les Chemins de Fer a L'Exposition de Chicago, (Paris, France: E Bernard et Cie, 1894), p 28-29. See also "World's Columbian Exposition-XI: Exhibit of Schenectady Locomotve Works," Engineering News, Volume , (25 May 1893), p. 483 (Thanks to Chris Hohl for his 26 July 2015 reminder of the actual origin and number of this class.) Schenectady works numbers for 60-73 were 4041-4049 in March 1893, 4145 in June, 4324-4326 in July 1895, 4327-4330 in August and 5412-5417 in April 1900 for 84-89. Baldwin built ten more to this design, but the image of page 99 of DeGolyer Baldwin Specifications collection, Volume 20, is not available. Works numbers were 14717-14722 in February 1896 (74-79) and 16747-16750 (80-83) in May 1899.

These Twelve-wheelers were part of a short-lived trend in which six axles seemed better than five for a big freight hauler. They were fitted with a brick arch and noted for their size. On the other hand, compared to many later 4-8-0s, these engines had a relatively short stroke.

According to a website on immigration (of all sources and on an appropriate day to discover it!) -- [], accessed 4 July 2007 -- these were the biggest of the time.

To be precise, Todd Lindahl's account of his family history includes the following caption:"'My grandfather Gust (Franz Gustaf but preferred to be called "Gust"). The picture was taken in the Duluth & Iron Range back shops in 1901. Gust is standing on the running board of the locomotive just to the left of the bell. The locomotive is number 70, a 4-8-0 mastodon type engine. When these engines arrived in 1893 they were the largest freight engines ever built.'"

The entire class remained in service into the late 1920s. All were withdrawn and scrapped by the end of 1933.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID8534
RailroadDuluth & Iron Range (DM&IR)
Number in Class30
Road Numbers60-89
Number Built30
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.50 / 4.72
Engine Wheelbase (ft / m)25.33 / 7.72
Ratio of driving wheelbase to overall engine wheebase 0.61
Overall Wheelbase (engine & tender) (ft / m)51.58 / 15.72
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)139,000 / 63,049
Engine Weight (lbs / kg)169,000 / 76,657
Tender Loaded Weight (lbs / kg)73,185 / 33,196
Total Engine and Tender Weight (lbs / kg)242,185 / 109,853
Tender Water Capacity (gals / ML)3168 / 12
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT) 7.20 / 6.50
Minimum weight of rail (calculated) (lb/yd / kg/m)58 / 29
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)54 / 1372
Boiler Pressure (psi / kPa)170 / 11.70
High Pressure Cylinders (dia x stroke) (in / mm)22" x 26" / 559x660
Tractive Effort (lbs / kg)33,674 / 15274.29
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.13
Heating Ability
Firebox Area (sq ft / m2)189.70 / 17.62
Grate Area (sq ft / m2)31.50 / 2.93
Evaporative Heating Surface (sq ft / m2)2402 / 223.15
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)2402 / 223.15
Evaporative Heating Surface/Cylinder Volume209.98
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5355
Same as above plus superheater percentage5355
Same as above but substitute firebox area for grate area32,249
Power L14481
Power MT284.28

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