Northern Minnesota didn't have much call for passenger service, but the Iron Range found a need for more power than the Ten-wheelers could provide. They bought these small Pacifics that possessed a free-steaming boiler and 14" piston valves. Locobase doesn't know if the quartet was delivered with superheaters, but if not, the railroad installed them before too long.
All four engines served the D & IR, the DM & N, and the DM & IR on the same rails for 40 years; retirements came in 1953-1955.
See the larger DM & N Pacifics delivered by Baldwin in the same year in Locobase 7284.
In the same time the Duluth & Iron Range took delivery of four light Pacifics (Locobase 7283), the same builder supplied these substantially larger engines to the DM & N.
Whereas the Iron Range's engines were branch-liners, the Northern's trio were headed to the main line. Free-steaming and fitted with 15" piston valves, these 4-6-2s served the DM & N and successor DM & IR into the 1950s before retiring in 1955 (401), 1958 (402), and 400 in 1959.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Duluth & Iron Range (DM&IR)||Duluth, Missabe & Northern (DM&IR)|
|Road Numbers||107-110 / 1107-1110||400-402|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.39||0.36|
|Overall Wheelbase (engine & tender)||63.04'||65.83'|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers||140000 lbs||173310 lbs|
|Engine Weight||223900 lbs||254600 lbs|
|Tender Light Weight||137400 lbs||171800 lbs|
|Total Engine and Tender Weight||361300 lbs||426400 lbs|
|Tender Water Capacity||6300 gals||8600 gals|
|Tender Fuel Capacity (oil/coal)||14 tons||14 tons|
|Minimum weight of rail (calculated)||78 lb/yard||96 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||200 psi||200 psi|
|Cylinders (dia x stroke)||22" x 28"||25" x 28"|
|Tractive Effort||33389 lbs||43116 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.19||4.02|
|Firebox Area||205 sq. ft||243.10 sq. ft|
|Grate Area||47.70 sq. ft||58.60 sq. ft|
|Evaporative Heating Surface||2716 sq. ft||3087 sq. ft|
|Superheating Surface||610 sq. ft||906 sq. ft|
|Combined Heating Surface||3326 sq. ft||3993 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||220.47||194.05|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||9540||11720|
|Same as above plus superheater percentage||11257||14416|
|Same as above but substitute firebox area for grate area||48380||59803|