Works numbers were:
5613-5614 in July 1900; 5616-5618 in August; 5615 in September
5840-5841 in April 1901; 5842-5843 in May; 6138-6143 in December
25411-25412 in July 1902; 25413-25414 in August; 25415-25416 in October; 26524-26529 in December
25571-25579 in July 1903
29705-29708 in September 1904, 29709-29716 in October
30293 in January 1905, 30294-30297 in May, 30298 in June
39247-39256 in May 1906
42200-42209 in May 1907.
Acquisition of this relatively large class of Atlantics began with six in 1900 and continued for eight years. They had the relatively unusual layout of piston valves 11" (279 mm) in diameter between the frames and acuated by inside link motion. The trailing truck rode on outside-bearing journals topped by leaf springs. They also had 28.27 sq ft (2.6 sq m) of arch tubes.
The journal called the engines "Northwesterns" and noted that although they'd been in service only a short time at time of writing, they were already proving much easier to fire than earlier locomotives. "The larger and better shaped grates and large heating surface make these very free-steaming engines. We are told that there is practically no black smoke, even when worked hard, and that the two doors are conducive to light firing."
They were also said to ride well.
See Locobase 14674 for the last batch of Ds, ten of which were delivered with Walschaert gear actuating Young rotary valve gear.
Locobase 2793 describes the D class in toto from its beginnings in 1900. Because this last batch weighed quite a bit more because of the Walschaert gear installation, had slightly different surface areas and a small difference in driver diameter, we've created a separate entry. The last ten had Young rotary valves and Walschaert gear.
All of these were later superheated; see Locobase 4363.
This reflects the superheating applied to members of the large class of Atlantics profiled in Locobase 2793. The book does not say when this program was implemented nor how many D-class Atlantics were involved.
See Locobase 9340 for the superheated update.
Larry Bohn, author of the website members.lsol.net/mollyandmic/c364.htm explains that these Omaha engines were very similar to the D-class Atlantics then being supplied to the Chicago & NorthWestern, the Omaha's parent. The data given here are after modification for superheating. Firebox heating surface includes 24.9 sq ft of arch tubes.
|Specifications by Steve Llanso of Sweat House Media|
|Class||D||D - late||D - superheated||G-3||G-3 - superheated|
|Railroad||Chicago & North Western (C&NW)||Chicago & North Western (C&NW)||Chicago & North Western (C&NW)||Chicago, St Paul, Minneapolis & Omaha (C&NW)||Chicago, St Paul, Minneapolis & Omaha (C&NW)|
|Number in Class||77||14||7||7|
|Road Numbers||125-128, 390-399||364-370||364-370|
|Locomotive Length and Weight|
|Driver Wheelbase (ft)||7||7||7||7||7|
|Engine Wheelbase (ft)||26.75||26.75||26.75||26.67||26.75|
|Ratio of driving wheelbase to overall engine wheebase||0.26||0.26||0.26||0.26||0.26|
|Overall Wheelbase (engine & tender) (ft)||57.94||58.62||57.94||57.90||57.94|
|Axle Loading (Maximum Weight per Axle) (lbs)|
|Weight on Drivers (lbs)||91,000||95,000||97,500||91,800||92,500|
|Engine Weight (lbs)||158,000||183,000||181,500||172,000||159,500|
|Tender Loaded Weight (lbs)||140,000||144,300||144,000||144,000||144,000|
|Total Engine and Tender Weight (lbs)||298,000||327,300||325,500||316,000||303,500|
|Tender Water Capacity (gals)||7500||7500||7500||5200||5200|
|Tender Fuel Capacity (oil/coal) (gals/tons)||10||10||10||10||10|
|Minimum weight of rail (calculated) (lb/yd)||76||79||81||77||77|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in)||80||81||81||81||81|
|Boiler Pressure (psi)||200||200||200||200||200|
|High Pressure Cylinders (dia x stroke) (in)||20" x 26"||20" x 26"||20" x 26"||20" x 26"||20" x 26"|
|Tractive Effort (lbs)||22,100||21,827||21,827||21,827||21,827|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.12||4.35||4.47||4.21||4.24|
|Firebox Area (sq ft)||199||197.10||199||195.60||195.60|
|Grate Area (sq ft)||46.30||46.30||46.27||46||46.27|
|Evaporative Heating Surface (sq ft)||3016||2956||2174||2817||2174|
|Superheating Surface (sq ft)||439||439|
|Combined Heating Surface (sq ft)||3016||2956||2613||2817||2613|
|Evaporative Heating Surface/Cylinder Volume||319.02||312.68||229.96||297.97||229.96|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||9260||9260||9254||9200||9254|
|Same as above plus superheater percentage||9260||9260||10,827||9200||10,827|
|Same as above but substitute firebox area for grate area||39,800||39,420||46,566||39,120||45,770|