Taken onto the NP roster when that railroad acquired the Skally Line, which was in 1900, the same year that this trio was delivered.
600 was scrapped in 1927, 601-602 went in 1932.
The main entry for this class is Locobase 889, which describes the two engines of this class that were delivered with superheaters.
After Baldwin delivered three Atlantics to the Northern Pacific (Locobases 16056 and 889), the railroad chose to superheat this engine with a different distribution of small and large tubes from the two that were delivered by Baldwin with superheaters.
Three engines representing a relatively rare wheel arrangement for the NP. These joined three St. Paul and Duluth N-1s acquired in 1900. This spec applies to the two Baldwins that were delivered with superheaters and 12" (305 mm) piston valves; 603 originally arrived with a saturated boiler; see Locobase 16056.
When superheated, 603 had 2,251 sq ft of EHS, 437 sq ft of SHS; tube and flue counted came to 185 2" tubes and 24 5 3/8" flues.
RV Nixon, in the Northern Pacific's Tell Tale (September, 1950) (http://www.employees.org/~davison/nprha/niftyfiftytelltale.html) gave an account of these rare birds:
"In the 1890s and early 1900s most of the railroads went overboard buying Atlantic or 4-4-2 type locomotives, particularly lines in the East where easy grades prevailed. The Atlantic was great for speed and low in tractive effort ...
"Northern Pacific, however, used good judgment in not falling for the Atlantic fad. Heavy trains, mountain grades and Atlantics were not a good combination. Only three engines of this type, 603-605, built by Baldwin in 1909, were purchased by the Northern Pacific. Three others, Class N, were taken over by the Northern Pacific when the St. Paul and Duluth Railroad was absorbed"
Nixon adds that many long-time NP employees never knew that Atlantics ran on their railroad. He supposes the explanation "...probably is due to the fact that the Atlantics, as far as we know, never worked west of Mandan. For the most part they were used on branches out of Mandan and Jamestown, as well as on the lines from Staples and St. Paul to Duluth ...."
|Specifications by Steve Llanso of Sweat House Media|
|Class||N||N-1 - 603||N-1 - 603 superheated||N-1 - 604-605|
|Railroad||St Paul & Duluth (NP)||Northern Pacific (NP)||Northern Pacific (NP)||Northern Pacific (NP)|
|Number in Class||3||1||1||2|
|Road Numbers||80-82 / 600-602||603||603||604-605|
|Builder||Burnham, Williams & Co||Burnham, Williams & Co||NP||Burnham, Williams & Co|
|Locomotive Length and Weight|
|Driver Wheelbase (ft)||7||6.83||6.83||6.83|
|Engine Wheelbase (ft)||25.08||27.83||27.83||27.83|
|Ratio of driving wheelbase to overall engine wheebase||0.28||0.25||0.25||0.25|
|Overall Wheelbase (engine & tender) (ft)||52.17||57.25|
|Axle Loading (Maximum Weight per Axle) (lbs)|
|Weight on Drivers (lbs)||74,600||100,000||100,800||100,800|
|Engine Weight (lbs)||140,500||180,000||197,050||197,050|
|Tender Loaded Weight (lbs)||93,200||122,800||127,340||127,340|
|Total Engine and Tender Weight (lbs)||233,700||302,800||324,390||324,390|
|Tender Water Capacity (gals)||4500||6000||6000||6000|
|Tender Fuel Capacity (oil/coal) (gals/tons)||8||9||9||9|
|Minimum weight of rail (calculated) (lb/yd)||62||83||84||84|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in)||78||73||73||73|
|Boiler Pressure (psi)||180||185||185||185|
|High Pressure Cylinders (dia x stroke) (in)||19" x 26"||21" x 26"||21" x 26"||21" x 26"|
|Tractive Effort (lbs)||18,411||24,699||24,699||24,699|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.05||4.05||4.08||4.08|
|Firebox Area (sq ft)||171||168||168||168|
|Grate Area (sq ft)||30.10||43.50||43.50||43.50|
|Evaporative Heating Surface (sq ft)||2217||2718||2251||2287|
|Superheating Surface (sq ft)||437||371|
|Combined Heating Surface (sq ft)||2217||2718||2688||2658|
|Evaporative Heating Surface/Cylinder Volume||259.84||260.77||215.97||219.42|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||5418||8048||8048||8048|
|Same as above plus superheater percentage||5418||8048||9335||9174|
|Same as above but substitute firebox area for grate area||30,780||31,080||36,053||35,431|