Duluth & Iron Range / Duluth, Missabe & Northern 4-6-2 "Pacific" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class A (Locobase 7283)

See data from DM&IR 6 -1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 39861-39864 in May 1913.

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.

Class P (Locobase 7284)

See data from DM&IR 6 -1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 39877-39879 in May 1913.

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
Locobase ID7283 7284
RailroadDuluth & Iron Range (DM&IR)Duluth, Missabe & Northern (DM&IR)
Number in Class43
Road Numbers107-110 / 1107-1110400-402
Number Built43
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase12.50'12.50'
Engine Wheelbase31.83'35'
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 Drivers140000 lbs173310 lbs
Engine Weight223900 lbs254600 lbs
Tender Light Weight137400 lbs171800 lbs
Total Engine and Tender Weight361300 lbs426400 lbs
Tender Water Capacity6300 gals8600 gals
Tender Fuel Capacity (oil/coal)14 tons14 tons
Minimum weight of rail (calculated)78 lb/yard96 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter69"69"
Boiler Pressure200 psi200 psi
Cylinders (dia x stroke)22" x 28"25" x 28"
Tractive Effort33389 lbs43116 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.19 4.02
Heating Ability
Firebox Area205 sq. ft243.10 sq. ft
Grate Area47.70 sq. ft58.60 sq. ft
Evaporative Heating Surface2716 sq. ft3087 sq. ft
Superheating Surface610 sq. ft906 sq. ft
Combined Heating Surface3326 sq. ft3993 sq. ft
Evaporative Heating Surface/Cylinder Volume220.47194.05
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation954011720
Same as above plus superheater percentage1125714416
Same as above but substitute firebox area for grate area4838059803
Power L11723418010
Power MT814.17687.30


If you have any railroad data such as diagram books, rail station plans or anything else that you would be willing to share, please contact us.