Duluth, Missabe & Northern 2-8-8-2 "Chesapeake" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class M (Locobase 317)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 35, p. 166. See also tables in 1930 Locomotive Cyclopedia. (Thanks to Chris Hohl for pointing out the tender capacity.) Works numbers were 35165-35172 in September 1910.

Eight Mallet compounds virtually identical with Virginian 600. The Minnesotans were fitted with a feedwater heater in the boiler that contained 1,694 sq ft of heating surface area, another 160 sq ft was held in a preheater in the steam circuit between the HP and LP cylinders. The Missabe included those areas in its calculation of evaporative heating surface.

The Baldwin specs guaranteed to "pull or push" 55 empty steel ore cars weighing 16 tons each and a 10-ton caboose up the 6-mile long (10-km) 2.2% ruling grade from the Duluth docks to Proctor at an average speed of 12 mph. Stoking these engines was sometimes a problem even when two firemen were used. Although capable of handling 85 empties on the steep grades when fitted with mechanical stokers, the smallish boilers restricted their speed when so engaged.

Workhorse engines that were later given Schmidt superheaters, Standard mechanical stokers (in 1925), and Elesco feedwater heaters (in 1930). These engines were followed by 4 more engines fitted with superheaters from the start.

Class M - superheated (Locobase 6653)

Data from 1951 DM & IR locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

When the M-class Mallets (see Locobase 317) were fitted with Schmidt superheaters, Standard mechanical stokers (in 1925), and Elesco feedwater heaters (in 1930), the result was as is shown here. The firebox heating surface now included thermic syphons.

Class M-1/M-2 (Locobase 318)

Data from DeGolyer, Vol 55, pp. 163. Works numbers were 43530-43531 in June 1916, 45769-45793 in June 1917.

Firebox fitted with arch tubes, which contributed a considerable 48 sq ft (4.5 sq m) to the heating surface total and large combustion chamber which added 108 sq ft (10 sq m). Fifteen-inch (381 mm) piston valves supplied steam to the cylinders.

Four Mallet compounds that followed the eight bought in 1910 (Locobase 317). They pulled empty ore trains up the ruling grade of 2.2% from the ore docks at Duluth and the Proctor yards and brought loaded cars back down; they weren't turned at either end. Of the seven miles of line, six followed the grade while winding around compensated curves of 6-10 percent.

One source says that 208-209 had 77-sq ft grate area, which is smaller than earlier engines and presumably was still harder to fire and that 210-211 reverted to the early 84-sq ft grate, yielding a GDF of 61,750 and a CHS/GA ratio of 78.02. The data comes from a January 1917 table in Railway Mechanical Engineer for "208" that uses the 84-sq-ft figure.

Frank A King, writing in the November 1980 Trains, confirms the 84-sq-ft figure and notes that overall length was 5 feet less because the firebox was moved 5 ft farther forward.

All were converted to simple expansion locomotives in the 1930s; see Locobase 319.

Class MS/etc (Locobase 319)

Data is for 208-209, rebuilt in 1931 and 1937, respectively, and is from the 1951 DM & IR locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection..

210 (class M-2S) was rebuilt in 1929 with virtually identical specs except for an EHS of 5,441 sq ft and CHS of 7,921 (SHS% of CHS 31.31, BDF 792, CHS/GA ratio 94.3). She was nicknamed Madame Queen.

211 was rebuilt in 1931 and had an EHS of 5621 sq ft and a CHS of 8101 sq ft (SHS% of CHS 30.61, BDF 774, CHS/GA ratio 96.44).

The 207 (class MS) was rebuilt along similar lines in 1931, but came out heavier at 444,650 lb on the drivers.

Specifications by Steve Llanso of Sweat House Media
ClassMM - superheatedM-1/M-2MS/etc
Locobase ID317 6653 318 319
RailroadDuluth, Missabe & Northern (DM&IR)Duluth, Missabe & Northern (DM&IR)Duluth, Missabe & Northern (DM&IR)Duluth, Missabe & Northern (DM&IR)
Number in Class8742
Road Numbers200-207200-206208-211208-209
Number Built842
BuilderBaldwinDM&IRBaldwinDM & IR
Valve GearWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft)40.25151515
Engine Wheelbase (ft)55.7558.1755.7555.33
Ratio of driving wheelbase to overall engine wheebase 0.72 0.26 0.27 0.27
Overall Wheelbase (engine & tender) (ft)83.548783.5483.83
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)406,600392,200415,200421,100
Engine Weight (lbs)448,100436,000470,200494,450
Tender Loaded Weight (lbs)171,900171,900176,800195,200
Total Engine and Tender Weight (lbs)620,000607,900647,000689,650
Tender Water Capacity (gals)9000900090009000
Tender Fuel Capacity (oil/coal) (gals/tons)16161621
Minimum weight of rail (calculated) (lb/yd)85828788
Geometry Relating to Tractive Effort
Driver Diameter (in)57575757
Boiler Pressure (psi)200200200200
High Pressure Cylinders (dia x stroke) (in)26" x 32"26" x 32"26" x 32"24" x 32" (4)
Low Pressure Cylinders (dia x stroke) (in)40" x 32"40" x 32"40" x 32"
Tractive Effort (lbs)90,70990,70990,709109,945
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.48 4.32 4.58 3.83
Heating Ability
Firebox Area (sq ft)255340379346
Grate Area (sq ft)84848484
Evaporative Heating Surface (sq ft)6890412254245592
Superheating Surface (sq ft)93111682480
Combined Heating Surface (sq ft)6890505365928072
Evaporative Heating Surface/Cylinder Volume350.39209.62275.83166.87
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation16,80016,80016,80016,800
Same as above plus superheater percentage16,80019,82419,82422,008
Same as above but substitute firebox area for grate area51,00080,24089,44490,652
Power L133335797727916,807
Power MT144.57260.69309.20703.93


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