In 1937, an order of 30 Class S-2s was delivered from Baldwin. These were given road numbers 201 through 230. A second order of 10 Class S-2s were delivered from Baldwin in 1940 (road numbers 231 through 240). The Class S-2 Northerns weighed 490,450 lbs, had 74" drivers, 26 x 32 cylinders, 285 lbs psi and had a tractive effort of 70,800 lbs.
Because of wartime needs, another order of 10 (road numbers 260 through 269) Class S-3 Northerns was delivered in 1943 from the American Locomotive Company. This class was designed to have 74" drivers, 26 x 32 cylinders, 250 lbs psi boiler pressure and weighed 460,000 lbs and had a tractive effort of 62,040 pounds.
There are two survivors: number 261, which is operational and number 265 at the Illinois Railway Museum in Union, IL. When 261 is not running, it is stored at the old GN Shops near Minneapolis Junction in Minneapolis, MN.
|Class||Road Numbers||Year Built||Builder|
|S-1||250 (ex 9700)||1930||Baldwin|
As with most Class 1 locomotives built in this period, the firebox's heating surface area included a variety of structures and supplements. The combustion chamber contributed 122 sq ft (11.3 sq m), thermic syphons (two in the firebox, one in the combustion chamber) 116.5 sq ft (10.8 sq m) and arch tubes 16.5 sq ft (1.5 sq m). The boiler's Coffin feedwater heater was to be "applied in recess provided in smoke box.". The 14" piston valves had 9" of travel.
This was the proof-of-concept Northern for the Milwaukee Road, Glischinski's account says that 9700 (works #61176 in December 1929) entered service in 1930 from Baldwin as a trial horse against the powerful F6 4-6-4s then in service. He contends that the S1 was a stretched F6 in any case. Baldwin called it a "Modified Mountain".
For the moment, the Milwaukee's passenger trains made do with the F6 and the 9700 was put to work pulling 5,000-ton freights on its own. In 1934, the 9700 began working passenger trains between Avery, Idaho and Othello, Washington. In February 1938, the West Milwaukee shops duplicated the 9700, by then renumbered 250, and rolled out the 251. (Glischinski notes that it was the last new locomotive from that facility.)
Engines 203 and 231-240 used 105.5 sq ft (9.8 sq m) of circulators to supplement firebox heating surface instead of the 147 sq ft (13.65 sq m) of thermic syphons installed in the rest. See the photo provided on 16 September 2008 by "Mark D" to the Chaski Forum http://www.chaski.org/railfan/viewtopic.php?f=2&t=835; it illustrates splendidly the arrangement of the tubes and the firebricks that lay on top of them. The firebox also had a combustion chamber.
These forty S-2s operated mostly as freight haulers from Bensenville to Council Bluffs, Iowa or St. Paul, Minn. Occasionally they'd hook up to the westbound Olympian if it trailed more than twelve cars.
Even before theWest Milwaukee shops produced the 251 (see Locobase 247), the Milwaukee Road had gone to Baldwin for its definitive Northerns. The first 28 were produced in October 1937 through February 1938
147 sq ft of thermic syphons contributed to the firebox heating surface as did the combustion chamber. They had 14" piston valves with 7 1/2" of travel. Engines 203 and 231-240 used 105 sq ft of circulators to supplement firebox heating surface; see Locobase 248 for the data.
These S-2s operated mostly as freight haulers from Bensenville (West Milwaukee) to Council Bluffs, Iowa or St. Paul, Minn. Occasionally they'd hook up to the westbound Olympian if it trailed more than 12 cars.
http://www.261.com/history/generations.shtml, last accessed 23 September 2007.
Firebox heating surface included 80.5 sq ft of circulators.
The last of the Milwaukee Road's Northerns, this design pieced together a Rock Island frame, a Delaware & Hudson boiler, and a Union Pacific tender. Like the 1940 batch from Baldwin, the boiler used circulators in place of thermic syphons. Glischinski's account says of this batch "...an Alco ad touted them as 'the last word in 4-8-4 design.' They featured roller bearings, special compensating lateral driving-box devices, and precision firing equipment."
Four were later converted to oil-burning and the engines saw out steam in both freight and passenger service with retirements coming in 1954-1956.
|Specifications by Steve Llanso|
|Class||S1||S2 - circulator||S2 - thermic syphon||S3|
|Railroad||Milwaukee Road (CMStP&P)||Milwaukee Road (CMStP&P)||Milwaukee Road (CMStP&P)||Milwaukee Road (CMStP&P)|
|Road Numbers||970 / 250-251||203, 231-240||201-202, 204-230||260-269|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.43||0.41||0.41||0.42|
|Overall Wheelbase (engine & tender)||88.33'||92.04'||96.04'||95.50'|
|Axle Loading (Maximum Weight per Axle)||65136 lbs|
|Weight on Drivers||258818 lbs||282320 lbs||282320 lbs||259300 lbs|
|Engine Weight||450840 lbs||490450 lbs||490450 lbs||460000 lbs|
|Tender Light Weight||289169 lbs||323000 lbs||397000 lbs||364100 lbs|
|Total Engine and Tender Weight||740009 lbs||813450 lbs||887450 lbs||824100 lbs|
|Tender Water Capacity||15000 gals||20000 gals||20000 gals||25000 gals|
|Tender Fuel Capacity (oil/coal)||20 tons||25 tons||25 tons||20 tons|
|Minimum weight of rail (calculated) on which locomotive could run||108 lb/yard||118 lb/yard||118 lb/yard||108 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||230 psi||285 psi||285 psi||250 psi|
|Cylinders (dia x stroke)||28" x 30"||26" x 32"||26" x 32"||26" x 32"|
|Tractive Effort||62137 lbs||70816 lbs||70816 lbs||62119 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.17||3.99||3.99||4.17|
|Firebox Area||549 sq. ft||536 sq. ft||578 sq. ft||505.50 sq. ft|
|Grate Area||103 sq. ft||106 sq. ft||106 sq. ft||96.20 sq. ft|
|Evaporative Heating Surface||5400 sq. ft||5468 sq. ft||5509 sq. ft||4478 sq. ft|
|Superheating Surface||2403 sq. ft||2336 sq. ft||2336 sq. ft||1438 sq. ft|
|Combined Heating Surface||7803 sq. ft||7804 sq. ft||7845 sq. ft||5916 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||252.57||278.07||280.16||227.73|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||23690||30210||30210||24050|
|Same as above plus superheater percentage||31034||39273||39273||29822|
|Same as above but substitute firebox area for grate area||165414||198588||214149||156705|