Green Bay & Western 2-8-2 "Mikado" Locomotives in the USA

The Green Bay & Western Railroad's 265 miles of railroad in Wisconsin required locomotives that were slightly lighter than most other railroads would use. It used "Moguls" and "Consolidation" on its main line long past the time most railroads had relegated them to branch line and switching duty. Upgrading rail and bridges allowed the GB&W to finally buy some "Mikados" in 1937. These were carefully specified because of weight restriction, but were about 50 tons heavier than the heaviest locomotives previously operated. There were just six ALCO built "Mikados" purchased with three arriving in 1937 and other three were added to the roster in 1939.

The first three locomotives, delivered in 1937, were designated as Class D-48 and were assigned road numbers 401-403. The last three, delivered in 1939, were designated as Class D-47 and assigned road numbers 404 through 406. These six locomotives had 64" diameter drivers, 22" x 30" cylinders, a 245 psi boiler pressure, they exerted 47,247 pounds of tractive effort.

Numbers 401 through 403 weighed 280,000 pounds. The firebox was 277 square feet which included 26 square feet of arch tubes, the evaporative heating surface was 2,745 square feet and with the superheater was 3,617 square feet.

Numbers 404 through 406 weighed 285,000 pounds. The firebox was 277 square feet which included 26 square feet of arch tubes, the evaporative heating surface was 2,937 square feet and with the superheater was 4,121 square feet. .

By 1950 steam service was gone on the GB&W and the six "Mikados" were retired. After retirement, all six locomotives were stored at Green Bay's Norwood Yard in the hopes a second hand buyer would come forward. They were finally scrapped for $6,000 each in 1956.

There are no surviving Green Bay & Western 2-8-2 "Mikado" type locomotives


ClassQty.Road NumbersYear BuiltBuilderNotes
D-47 3401-4031937 ALCO1
D-47 3404-4061939ALCO2
  1. Numbers 401-403 scrapped in 1956
  2. Numbers 404-406 scrapped in 1956

Class Details by Steve Llanso of Sweat House Media

Class D-47 (Locobase 15)

Data from Builder's Card for #406 dated October 1939 and depicting Order No S-1815, found in the Green Bay Route website at [] . (Thanks to Chris Hohl for his 21 November 2015 email pointing Locobase to the Green Bay & Western site and the builder's card, and his 2 February 2016 email noting the absence of a valve gear, which he reported correctly as Walschaert and for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error .) See also tables in 1947 Locomotive Cyclopedia.

A late Mike design with late-steam tube-to-flue ratio, but no change in the firebox that had 26 sq ft (2.42. sq m) of arch tubes included in the heating surface area. This was a subclass that followed the first three D-47s (Locobase 4950) by two years -- the earlier engines had a more conservative tube-flue arrangement.

All three of the 1939 batch arrived in October 1939 and each cost $91,667. Like the earlier trio, these engines could easily manage fast freights at speeds up to 65 mph (105 kph).

All three were retired in early March 1950.

Class D-47 (Locobase 4950)

Data from Alco builder's card dated January 1937 and showing order S-1762, road number 401-403.

Many years after creating his first GB&W D-47 entry (Locobase 15), Locobase's compiler discovered that there were really two sub-classes. According to the builder's information that accompanied the first group, the tube-flue ratios were old school -- lots of 2" tubes, several dozen 5 1/2" flues. But Locobase's 15, which was based on the 1947 Locomotive Cyclopedia entries, showed a "superpower" arrangement of many fewer 2" tubes, many more 3 1/2" flues. The latter's table, however, covered 404-406, which were delivered two years after the first three. The firebox was the same in all six and included 26 sq ft of arch tubes in its heating surface area.

These three, like the later three, served only until 1950, pulling freights at speeds of up to 65 mph (105 kph). Locobase doubts whether they were brought up to the later standard with a new boiler, but cannot say for sure.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID15 4950
RailroadGreen Bay & WesternGreen Bay & Western
Number in Class33
Road Numbers404-406401-403
Number Built33
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)16.80 / 5.1216.75 / 5.11
Engine Wheelbase (ft / m)36.90 / 11.2536.90 / 11.25
Ratio of driving wheelbase to overall engine wheebase 0.46 0.45
Overall Wheelbase (engine & tender) (ft / m)72.18 / 2272.18 / 22
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)204,000 / 92,533201,800 / 91,535
Engine Weight (lbs / kg)285,000 / 129,274280,000 / 127,006
Tender Loaded Weight (lbs / kg)176,000 / 79,832174,300 / 79,061
Total Engine and Tender Weight (lbs / kg)461,000 / 209,106454,300 / 206,067
Tender Water Capacity (gals / ML)9000 / 34.099000 / 34.09
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)14 / 12.7014 / 12.70
Minimum weight of rail (calculated) (lb/yd / kg/m)85 / 42.5084 / 42
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)64 / 162664 / 1626
Boiler Pressure (psi / kPa)245 / 16.90245 / 16.90
High Pressure Cylinders (dia x stroke) (in / mm)22" x 30" / 559x76222" x 30" / 559x762
Tractive Effort (lbs / kg)47,247 / 21430.9047,247 / 21430.90
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.32 4.27
Heating Ability
Firebox Area (sq ft / m2)277 / 25.73277 / 25.74
Grate Area (sq ft / m2)60.40 / 5.6160.40 / 5.61
Evaporative Heating Surface (sq ft / m2)2937 / 272.962745 / 255.11
Superheating Surface (sq ft / m2)1184 / 110.04872 / 81.04
Combined Heating Surface (sq ft / m2)4121 / 3833617 / 336.15
Evaporative Heating Surface/Cylinder Volume222.52207.97
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation14,79814,798
Same as above plus superheater percentage19,08918,350
Same as above but substitute firebox area for grate area87,54684,153
Power L129,65623,716
Power MT1281.961036.37

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Wes Barris