Green Bay & Western 2-8-2 "Mikado" Locomotives of 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


Roster by Richard Duley

ClassQty.Road NumbersYear BuiltBuilderNotes
D-47 3401-4031937 ALCO1
D-47 3404-4061939ALCO2
Notes:
  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 http://www.greenbayroute.com/s_406_1939.htm . (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.) 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 the 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 #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.

Specifications by Steve Llanso of Sweat House Media
ClassD-47D-47
Locobase ID15 4950
RailroadGreen Bay & WesternGreen Bay & Western
CountryUSAUSA
Whyte2-8-22-8-2
Number in Class33
Road Numbers404-406401-403
GaugeStdStd
Number Built33
BuilderAlcoAlco
Year19391937
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase16.80'16.75'
Engine Wheelbase36.90'36.90'
Ratio of driving wheelbase to overall engine wheebase 0.46 0.45
Overall Wheelbase (engine & tender)72.18'72.18'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers204000 lbs201800 lbs
Engine Weight285000 lbs280000 lbs
Tender Light Weight176000 lbs174300 lbs
Total Engine and Tender Weight461000 lbs454300 lbs
Tender Water Capacity9000 gals9000 gals
Tender Fuel Capacity (oil/coal)14 tons14 tons
Minimum weight of rail (calculated)85 lb/yard84 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter64"64"
Boiler Pressure245 psi245 psi
Cylinders (dia x stroke)22" x 30"22" x 30"
Tractive Effort47247 lbs47247 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.32 4.27
Heating Ability
Firebox Area277 sq. ft277 sq. ft
Grate Area60.40 sq. ft60.40 sq. ft
Evaporative Heating Surface2937 sq. ft2745 sq. ft
Superheating Surface1184 sq. ft872 sq. ft
Combined Heating Surface4121 sq. ft3617 sq. ft
Evaporative Heating Surface/Cylinder Volume222.52207.97
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1479814798
Same as above plus superheater percentage1908918350
Same as above but substitute firebox area for grate area8754684153
Power L12965623716
Power MT1281.961036.37

Photos


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