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.
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.
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.
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) .
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|
|Class||L-1 - 1st batch||L-1 - 2nd batch||L-1 -S||L-2||L-2 -S|
|Railroad||Great Northern (GN)||Great Northern (GN)||Great Northern (GN)||Great Northern (GN)||Great Northern (GN)|
|Number in Class||5||20||2||50||8|
|Road Numbers||1800-1804 / 1900-1904||1905-1924||1902, 1921||1805-1854||1814-16, 1822, 1824-26+|
|Builder||Burnham, Williams & Co||Burnham, Williams & Co||GN||Burnham, Williams & Co||GN|
|Locomotive Length and Weight|
|Driver Wheelbase (ft)||10||10||10||9.83||9.83|
|Engine Wheelbase (ft)||44.83||44.83||44.83||43.58||43.58|
|Ratio of driving wheelbase to overall engine wheebase||0.22||0.22||0.22||0.23||0.23|
|Overall Wheelbase (engine & tender) (ft)||73.17||73.17||73.19||72.02||71.60|
|Axle Loading (Maximum Weight per Axle) (lbs)||52,667||52,667||41,667|
|Weight on Drivers (lbs)||316,000||321,450||316,000||250,000||250,000|
|Engine Weight (lbs)||355,000||362,150||355,000||280,000||288,000|
|Tender Light Weight (lbs)||148,000||152,700||148,200||152,700||163,000|
|Total Engine and Tender Weight (lbs)||503,000||514,850||503,200||432,700||451,000|
|Tender Water Capacity (gals)||8000||8000||8000||8000||8000|
|Tender Fuel Capacity (oil/coal) (gals/tons)||13||13||13||13||16|
|Minimum weight of rail (calculated) (lb/yd)||88||89||88||69||69|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in)||55||55||55||55||55|
|Boiler Pressure (psi)||200||200||200||210||200|
|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)||64,193||64,193||74,525||54,999||52,380|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.92||5.01||4.24||4.55||4.77|
|Firebox Area (sq ft)||230||225||230||198||206|
|Grate Area (sq ft)||78||78||78||53.40||78|
|Evaporative Heating Surface (sq ft)||5703||5658||4230||3906||3089|
|Superheating Surface (sq ft)||1070||725|
|Combined Heating Surface (sq ft)||5703||5658||5300||3906||3814|
|Evaporative Heating Surface/Cylinder Volume||424.13||420.78||252.46||358.08||283.18|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||15,600||15,600||15,600||11,214||15,600|
|Same as above plus superheater percentage||15,600||15,600||18,720||11,214||18,564|
|Same as above but substitute firebox area for grate area||46,000||45,000||55,200||41,580||49,028|