Wabash 4-8-4 "Northern" Locomotives in the USA

The Wabash Railroad ordered 25 "Northerns" from the Baldwin Locomotive Works and took delivery of eighteen of the 4-8-4s in 1930. The order was completed when another six were received in 1931. These Northerns designated Class O-1 were assigned road numbers 2900 through 2924 and were put to work hauling freight.

Their design included 70" drivers, 27 x 32 cylinders, a 250 psi boiler pressure, a weight of 454,090 lbs and a tractive effort of 70,817 pounds.

The Class O-1 Northerns were scrapped starting in October, 1955 and by February, 1956 all had been retired. None of the Wabash Northerns remain today.

Class Details by Steve Llanso of Sweat House Media

Class O1 (Locobase 285)

Data from tables and diagram in 1930 Locomotive Cyclopedia, WAB 1 Locomotive, Crane and Marine diagrams book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 81, pp. 260+. (Thanks to Chris Hohl for pointing out the proper year for the first deliveries of this class and for David Popp II for his March 2016 comment concerning the original tender weight and capacities.)

Baldwin produced this class over a seven-month period as the Great Depression deepened. Works numbers were:

Walschaert valve gear --

61417-18 in June 1930, 61435-61438 in July, 61482-61485 in September, 61516-61521 in October, 61567-68 in November, 61572 in December.

Baker valve gear -- 61588-61593 in January 1931.

Firebox heating surface included 30 sq ft (2.8 sq m) of arch tubes and 95.5 sq ft (8.8 sq m) of thermic syphons; 2917 had a thermic syphon in the combustion chamber that added 16.5 sq ft (1.5 sq m). The Worthington Type 5-S feedwater heater was located on the left side.

The first 20 used Walschaert gear, the last five operated Baker valve gear. The latter weighed about a ton more, though Locobase doesn't think all of the increase is attributable to the change in valve gear. Piston valves measured 12" (306 mm) in diameter with 8" (203 mm) travel using Walschaert gear, 9" (227 mm) using Baker.

As reported by David Popp, tenders as delivered carried 18 tons of coal and weighed about 281,000 lb (127,460 kg). Like the M1s, the O1 tender coal capacity grew to 23 tons (20.9 tonnes); loaded tender weight increased to 307,510 lb (139,484 kg).

Drury (1993) notes the strong similarities between these Northerns and 25 4-8-2 Mountains (Locobase 1407) delivered by the same builder to the same railroad at the same time for the same service (freights between Montpelier, Ohio and Decatur, Illinois) and adds: "The question 'Why not 50 of one type?' remains unanswered."

An article in Railway Age 14 February 1931 doesn't answer the question, certainly, saying only that the chief difference between the two was the larger grate in a longer, wider firebox. Comparing specs shows other noticeable differences like the 24 ton difference in loaded engine weight and an additional foot of tube and flue length. Other ratios indicate a determination to retain the same relatively high direct heating percentage and DHS/grate area ratio and the ratio of evaporative heating surface area to grate area.

Like most Wabash steam, these engines were retired in the mid-1950s

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID285
Number in Class25
Road Numbers2900-2924
Number Built25
Valve GearBaker or Walschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)18.25 / 5.56
Engine Wheelbase (ft / m)45 / 13.72
Ratio of driving wheelbase to overall engine wheebase 0.41
Overall Wheelbase (engine & tender) (ft / m)86.83 / 26.47
Axle Loading (Maximum Weight per Axle) (lbs / kg)69,500 / 31,525
Weight on Drivers (lbs / kg)274,100 / 124,330
Engine Weight (lbs / kg)454,090 / 205,972
Tender Loaded Weight (lbs / kg)281,000 / 127,460
Total Engine and Tender Weight (lbs / kg)735,090 / 333,432
Tender Water Capacity (gals / ML)15,000 / 56.82
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)23 / 20.90
Minimum weight of rail (calculated) (lb/yd / kg/m)114 / 57
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)70 / 1778
Boiler Pressure (psi / kPa)250 / 17.20
High Pressure Cylinders (dia x stroke) (in / mm)27" x 32" / 686x813
Tractive Effort (lbs / kg)70,817 / 32122.09
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.87
Heating Ability
Firebox Area (sq ft / m2)495 / 45.99
Grate Area (sq ft / m2)96.25 / 8.94
Evaporative Heating Surface (sq ft / m2)5189 / 482.07
Superheating Surface (sq ft / m2)2360 / 219.25
Combined Heating Surface (sq ft / m2)7549 / 701.32
Evaporative Heating Surface/Cylinder Volume244.70
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation24,063
Same as above plus superheater percentage31,522
Same as above but substitute firebox area for grate area162,113
Power L139,755
Power MT1279.02

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