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|
|Ratio of driving wheelbase to overall engine wheebase||0.26||0.26||0.26||0.26||0.26|
|Overall Wheelbase (engine & tender)||57.94'||58.62'||57.94'||57.90'||57.94'|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers||91000 lbs||95000 lbs||97500 lbs||91800 lbs||92500 lbs|
|Engine Weight||158000 lbs||183000 lbs||181500 lbs||172000 lbs||159500 lbs|
|Tender Light Weight||140000 lbs||144300 lbs||144000 lbs||144000 lbs||144000 lbs|
|Total Engine and Tender Weight||298000 lbs||327300 lbs||325500 lbs||316000 lbs||303500 lbs|
|Tender Water Capacity||7500 gals||7500 gals||7500 gals||5200 gals||5200 gals|
|Tender Fuel Capacity (oil/coal)||10 tons||10 tons||10 tons||10 tons||10 tons|
|Minimum weight of rail (calculated)||76 lb/yard||79 lb/yard||81 lb/yard||77 lb/yard||77 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||200 psi||200 psi||200 psi||200 psi||200 psi|
|Cylinders (dia x stroke)||20" x 26"||20" x 26"||20" x 26"||20" x 26"||20" x 26"|
|Tractive Effort||22100 lbs||21827 lbs||21827 lbs||21827 lbs||21827 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.12||4.35||4.47||4.21||4.24|
|Firebox Area||199 sq. ft||197.10 sq. ft||199 sq. ft||195.60 sq. ft||195.60 sq. ft|
|Grate Area||46.30 sq. ft||46.30 sq. ft||46.27 sq. ft||46 sq. ft||46.27 sq. ft|
|Evaporative Heating Surface||3016 sq. ft||2956 sq. ft||2174 sq. ft||2817 sq. ft||2174 sq. ft|
|Superheating Surface||439 sq. ft||439 sq. ft|
|Combined Heating Surface||3016 sq. ft||2956 sq. ft||2613 sq. ft||2817 sq. ft||2613 sq. ft|
|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||10827||9200||10827|
|Same as above but substitute firebox area for grate area||39800||39420||46566||39120||45770|