Great Northern 2-8-8-0 "Consolidation Mallet" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class N-1 (Locobase 307)

Data from Recent Construction #91 (Baldwin Locomotive Works, 1918), p. 28-29. See also DeGolyer, Volume 42, pp. 286+. See also "Oil versus Coal Burning Locomotives" , The Commercial and Financial Chronicle - Railway and Industrial Section, Volume LXXXXII (92), No 2392 (29 April 1911), pp. 3-4. See also "Railroad Cooperation", Proceedings of the Western Forestry and Conservation Association, Issue 2 (Seattle, Wash., 2-3 December 1912), pp. 23-.27. (Thanks to Chris Hohl for his 30 May 2016 email noting the original tender capacities and weights and his 5 May 2022 email correcting the engine wheelbase.) Works numbers were 38074 in July 1912; 38130-38132, 38167, 38186-38189, 38225-38228 in August; and 38281-38284, 38371-38373, 38382-38384, 38415-38416 in September..

Originally built by Great Northern with relatively tall drivers for a compound articulated. They presented an imposing appearance, showing a high Belpaire boiler over ten axles of running gear. Firebox heating surface included 81 sq ft (7.53 sq m) of combustion chamber All four cylinders were fed through 15" (381 mm) piston valves.

The last eight were oil burners and trailed tenders carrying the same amount of water as the first 17, but holding 4,500 US gallons (17,033 litres) of fuel oil. The 1911 C&FC article discussing oil firing noted "Oil has lately taken an aggressive stride forward in its rivalyr with coal as a fuel for engines."

The report explained in some detail why the GN was looking toward the liquid fuel: "[M]atters have evidently been hastened in the introduction of oil-burning locomotives by the forest dcvastations of last year. [1910]. Minneapolis lumbermen, who have investments in Washington, where the fires were so long beyond control, interested themselves in urging the substitution of oil-burning engines for coal burners. President Louis W. Hill investigated the question from the standpoint of safety to the forests and economy."

The results seemed decisive: " On both grounds the inquiry proved satisfactory for the oil burners and the order for conversion was given. No fewer than 115 Great Northern locomotives are being overhauled this spring and changed from coal burners to oil burners. For their requirements a storage plant of 7,000,000 gallons is being erected at Everett, Washington, and the oil will be delivered there by ship from California."

See the Proceedings of the WF&CA discussion of

The Baldwin specs describe the Emerson "New Type" superheater. The engines were big and superheated and presumably presented some new challenges. So the specs contain some "Hereafter" notes tweaking details. One, however, implied a higher level of urgency. Referring to a letter from F A Neely received on 3 November 1912, the note said "Give particular attention to riveting of cylinder saddles and caulking of same."

"Leaky seams" forced the railroad to remove lagging from all the boilers in the first batch save that of 2016 and caulk them. A least some high-pressure cylinders leaked and the flexible stay bolts at the back end of the combustion chamber either required redesign or at least more stays. (The firebox had 900 Tate flexible staybolts in all as well as 200 Tate expansion staybolts on the entire roof of the combustion chamber.)

The N-1s were simpled in the 1920s, becoming N-2s and later N-3s in the process (Locobases 2802 and 6445, respectively).

Class N-2 (Locobase 2802)

Data from GN - 1 1929 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for his 12 May 2021 email supplying the correct tender weight and wheelbase for the oil burners and his 5 May 2022 email correcting the engine wheelbase.)

These were the tallest locomotives on the Great Northern because the designers had to get the large firebox above the rearmost driving axle. Delivered as N-1 compounds by Baldwin in 1912 (Locobase 307), these engines were simpled in the mid-1920s, using Worthington feedwater heaters and generating 100,200 lb of tractive effort. The Belpaire firebox with its 81 sq ft (7.53 sq m) in the combustion chamber and 36 sq ft (3.34 sq m) arch remained unchanged. They did get 13" (330 mm) piston valves on all four cylinders. Moreover, the boiler sacrificed 64 small tubes for 18 more flues to accommodate a considerable increase in superheater area.

2001, 2003, 2005, 2008-2009, 2013, and 2016 were converted to oil burning and trailed shorter Vanderbilt tenders numbered 2092-2099 that weighed 310,500 lb (140,861 kg) when carrying 17,000 US gallons (64,345 litres) of water and 4,600 gallons (17,411 litres) of fuel oil. Engine and tender wheelbase measured 92 ft 3 1/2 in (28,13 m).

In the early 1940s they got new frames and roller bearings as well as a larger grate; at that point they became N-3s; see Locobase 6445

Class N-3 (Locobase 6445)

Data from [] (visited 7 January 2005). See also GN 4 - 1946 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange; Charles R. Wood, Lines West (New York: Bonanza Books, 1967), p 109; and S Kip Farrington, Jr, Railroading Coast to Coast (New York: Bonanza Books, 1976), p. 156. (Thanks to Chris Hohl for his 5 May 2022 email correcting the engine wheelbase and for noting the working boiler pressure. He also supplied a spreadsheet outlining tender differences among the 25 engines.)

Delivered as N-1 compounds by Baldwin in 1912 (Locobase 307), these engines were simpled in the mid-1920s (N-2; Locobase 2802). Note that they still had the characteristic Belpaire firebox.

In the early 1940s, the N-2 class (Locobase 2802) got new General Steel Casting Co cast-steel beds, new Baldwin-built nickel-steel boilers, and Timken roller bearings as well as a larger grate; at that point they became N-3s. Piston valve diameters still measured 13" (330 mm). Fifteen received "semi-streamlined" cabs.

The reworked Belpaire firebox included a larger combustion chamber contributing 144 sq ft (13.38 sq m) to firebox heating surface area. An additional 33 sq ft (3.07 sq m) came from arch tubes. Although the 1946 diagram books showed all 25 retained the four arch tubes, the 1952 diagram books presented a different firebox, as revealed in Hohl's spreadsheet. The arch tubes had been deleted, but 80 sq ft (7.43 sq m) of security circulators installed. The two changes resulted in 483 sq ft (44.87 sq m) of direct heating surface area, which accounted for 8.32% of the 5,805 sq ft (539.30 sq m) of evaporative heating surface area.

A comparison with the 1912 compound N-1's factors (Locobase 307) shows what a huge increase in power these rebuilds represented. Chris Hohl noted that although the boiler had a designed pressure of 300 psi (20.7 bar), all of them had a working pressure of 265 psi.)

The railway substituted exhaust steam injectors for the Worthington feed water heaters installed in the 1920s. Elesco supplied the injectors for 2000, 2003-2009, 2016, and 2022. 2012 had one Elesco and one Sellers injector. The other fourteen had Sellers injectors. Below the boiler, the railroad installed Timken roller bearings on all driving axles.

Chris Hohl pointed out that as of 1946, oil burners (13) only slightly outnumbered coal burners (12). Of the oil burners, seven (2000, 2003, 2005, 2008-2009, 2013-2017) trailed the tenders shown in Locobase's specs; all 25 would use that tender by 1952. The other 6 (2004, 2006-2007, 2016, 2019, 2022) used slightly heavier tenders weighing 374,500 lb(169,871 kg) when filled with 5,700 US gallons (21,575 litres) of oil and 21,500 gallons (81,378 litres) of water.

All twelve coal burners carried 24 short tons of coal. Eleven (2001-2002, 2011-2012, 2014-2015, 2018, 2020-2021, 2023-2024) used tenders carrying 21,500 US gallon of water while the 2010 had the 22,000 gallon capacity tender. Loaded coal tender weights varied little: Ten put 365,400 lb (165,742 kg) on the rails, the eleventh slightly more at 365,600 lb (165,833 kg). The 2010's 363,880 lb (165,053 kg) was the lightest despite having 500 gallons more of water.

The timing couldn't have been better, either. The first of the rebuilds (2024) was completed on 10 February 1940, the last (2009) wrapping up almost exactly two years later on 12 February 1942. Thus the greater horsepower was available in time for the Great Northern's World War II traffic spike.

And did the N-3s ever deliver, according to Charles R. Wood. He described them as: "Amazing engines, they hauled ore on the iron range, hustled time freights on the Kalispell Division and served in heavy duty passenger service on troop trains." On the latter service, Wood quotes Mr. J S Miller, Assistant to the Superintendent of Motive Power in 1945/46 as saying that N-3s could " like a deer" and hit speeds of 50-60 mph (81-97 kph).

S Kip Farrington recorded a 17 November 1943 cab ride on Extra 2014 East as it pulled 180 cars weighing a total of 16,740 tons (15,218 tonnes).

Virtually all of the class was retired in 1955.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID307 2802 6445
RailroadGreat Northern (GN)Great Northern (GN)Great Northern (GN)
Number in Class252525
Road Numbers2000-20242000-20242000-2024
Number Built25
Valve GearWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)33 / 10.0633 / 10.0633 / 10.06
Engine Wheelbase (ft / m)52.50 / 1652.50 / 13.1852.50 / 13.18
Ratio of driving wheelbase to overall engine wheelbase 0.63 0.63 0.63
Overall Wheelbase (engine & tender) (ft / m)87.75 / 26.7598 / 29.8799 / 30.38
Axle Loading (Maximum Weight per Axle) (lbs / kg)52,500 / 23,81452,500 / 23,81457,400 / 26,036
Weight on Drivers (lbs / kg)420,000 / 190,509420,000 / 190,509459,200 / 208,290
Engine Weight (lbs / kg)450,000 / 204,117450,000 / 204,117489,200 / 221,898
Tender Loaded Weight (lbs / kg)154,000 / 69,853365,400 / 165,743365,400 / 165,743
Total Engine and Tender Weight (lbs / kg)604,000 / 273,970815,400 / 369,860854,600 / 387,641
Tender Water Capacity (gals / ML)8000 / 30.3021,500 / 81.4421,500 / 81.44
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)13 / 1224 / 225800 / 21,953
Minimum weight of rail (calculated) (lb/yd / kg/m)88 / 4488 / 4496 / 48
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)63 / 160063 / 160063 / 1600
Boiler Pressure (psi / kPa)210 / 14.50210 / 14.50265 / 18.30
High Pressure Cylinders (dia x stroke) (in / mm)28" x 32" / 711x81325" x 32" / 635x813 (4)22" x 32" / 559x813 (4)
Low Pressure Cylinders (dia x stroke) (in / mm)42" x 32" / 1067x813
Tractive Effort (lbs / kg)98,422 / 44643.52113,333 / 51407.05110,751 / 50235.87
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.27 3.71 4.15
Heating Ability
Tubes (number - dia) (in / mm)332 - 2.25" / 57268 - 2.25" / 57268 - 2.25" / 57
Flues (number - dia) (in / mm)42 - 5.5" / 14060 - 5.5" / 14060 - 5.5" / 140
Flue/Tube length (ft / m)24 / 7.3224 / 7.3222 / 6.71
Firebox Area (sq ft / m2)326 / 30.29359 / 33.35436 / 40.51
Grate Area (sq ft / m2)78.40 / 7.2878.40 / 7.2995 / 8.83
Evaporative Heating Surface (sq ft / m2)6446 / 598.855837 / 542.475782 / 537.16
Superheating Surface (sq ft / m2)1368 / 127.091868 / 173.612188 / 203.27
Combined Heating Surface (sq ft / m2)7814 / 725.947705 / 716.087970 / 740.43
Evaporative Heating Surface/Cylinder Volume282.63160.53205.33
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation16,46416,46425,175
Same as above plus superheater percentage19,42820,41531,972
Same as above but substitute firebox area for grate area80,78393,484146,736
Power L1876114,82427,325
Power MT367.90622.501049.50

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Wes Barris