Great Northern 2-6-6-2 Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class L-1 - 1st batch (Locobase 5354)

Data from GN 1916 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 28601, 28641 in July 1906; 28739, 28854 in August; and 28933 in September.

These were the first locomotives built with this wheel arrangement, which united the pulling power of the 0-6-6-0 that ran so successfully on the B&O with both lead and trailing trucks for more flexible operation. A distinguishing feature was the long Belpaire firebox, but a very small percentage of heating surface being direct.

These first five performed as helpers in the Cascades, the next 45 went out on the road themselves. The CB & Q bought 3 identical T-1s (Locobase 1047) in 1908.

Class L-1 - 2nd batch (Locobase 819)

Soon after the first quintet of L-1s came on the range, the Great Northern bought some smaller L-2s (Locobase 3554). Works numbers were 32722-32725, 32732, 32734-32735, 32740-32743, 32746-32749 in March 1908; 32755, 32758-32761 in April.

One can guess that those engines weren't quite powerful enough, so the GN tweaked the L-1 design slightly (yielding a slightly smaller boiler) and ordered the 20 more in 1908 that are shown in the current entry.

The Northern Pacific purchased the same design in the form of 16 Zs (Locobase 1046) in the same year. Western Maryland's 9 M-1s (Locobase 8321) used the same boiler and firebox, but had larger HP cylinders.

Class L-1 -S (Locobase 8854)

Data from GN 1916 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

At least two of the GN's L-1 2-6-6-2s (Locobase 5334) were superheated. In the process, the HP cylinders grew by 2 1/2" while the boiler's overall heating surface remained nearly the same. As these two were converted to O-6 Mikados in 1926 (Locobase 7449) as well as the rest of the class, the program must not have been very extensive.

Class L-2 (Locobase 3554)

Data from table in June 1908 American Engineer and Railroad Journal. Works numbers were 30400, 30422, 30445-30446 in March 1907; 30563-30565, 30588 in April; 30800-30803, 30846-30848, 30918-30919, 30943 in May; 31002-31004, 31065, 31105 in June; 31183-31184 in July; 32688-32691, 32696-32711 in February 1908.

These were smaller than the earlier L-1s (Locobase 5354), with a boiler, says Drury (1993) taken from the H-2 Pacifics. Small Mallets with Belpaire fireboxes, these engines weren't repeated as the Great Northern went for much bigger articulateds. Northern Pacific bought 6 copies in the same year (Locobase 821) .

Class L-2 -S (Locobase 8855)

Data from GN 1916 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

Although the GN found its 2-6-6-2s unremarkable, the railroad still superheated some of these pocket Mallets. Leaving the Belpaire firebox and the power dimensions alone, the shops performed the usual exchange of fire-tubes for flues. Most kept their HP slide valves, but three traded in for piston valves. Like the L-1, the class was rebuilt as 2-8-2s (O-5 class; Locobase 7450) in the 1920s.

Specifications by Steve Llanso of Sweat House Media
ClassL-1 - 1st batchL-1 - 2nd batchL-1 -SL-2L-2 -S
Locobase ID5354 819 8854 3554 8855
RailroadGreat Northern (GN)Great Northern (GN)Great Northern (GN)Great Northern (GN)Great Northern (GN)
Number in Class5202508
Road Numbers1800-1804 / 1900-19041905-19241902, 19211805-18541814-16, 1822, 1824-26+
Number Built52050
BuilderBurnham, Williams & CoBurnham, Williams & CoGNBurnham, Williams & CoGN
Valve GearWalschaertWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft)101010 9.83 9.83
Engine Wheelbase (ft)44.8344.8344.8343.5843.58
Ratio of driving wheelbase to overall engine wheebase 0.22 0.22 0.22 0.23 0.23
Overall Wheelbase (engine & tender) (ft)73.1773.1773.1972.0271.60
Axle Loading (Maximum Weight per Axle) (lbs)52,66752,66741,667
Weight on Drivers (lbs)316,000321,450316,000250,000250,000
Engine Weight (lbs)355,000362,150355,000280,000288,000
Tender Light Weight (lbs)148,000152,700148,200152,700163,000
Total Engine and Tender Weight (lbs)503,000514,850503,200432,700451,000
Tender Water Capacity (gals)80008000800080008000
Tender Fuel Capacity (oil/coal) (gals/tons)1313131316
Minimum weight of rail (calculated) (lb/yd)8889886969
Geometry Relating to Tractive Effort
Driver Diameter (in)5555555555
Boiler Pressure (psi)200200200210200
High Pressure Cylinders (dia x stroke) (in)21.5" x 32"21.5" x 32"24" x 32"20" x 30"20" x 30"
Low Pressure Cylinders (dia x stroke) (in)33" x 32"33" x 32"33" x 32"31" x 30"31" x 30"
Tractive Effort (lbs)64,19364,19374,52554,99952,380
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.92 5.01 4.24 4.55 4.77
Heating Ability
Firebox Area (sq ft)230225230198206
Grate Area (sq ft)78787853.4078
Evaporative Heating Surface (sq ft)57035658423039063089
Superheating Surface (sq ft)1070725
Combined Heating Surface (sq ft)57035658530039063814
Evaporative Heating Surface/Cylinder Volume424.13420.78252.46358.08283.18
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation15,60015,60015,60011,21415,600
Same as above plus superheater percentage15,60015,60018,72011,21418,564
Same as above but substitute firebox area for grate area46,00045,00055,20041,58049,028
Power L139663926868735967446
Power MT166.02161.56363.64190.27393.97



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