Milwaukee Road 4-8-4 "Northern" Type Locomotives

Introduction

The Chicago, Milwaukee, St. Paul & Pacific Railroad's own motive power department designed a Class S-1, 4-8-4 in 1930. It was built by the Baldwin Locomotive Works and put on the roster as number 9700. It remained the lone Northern on the CMStP&P for the next seven years. A second one-of-a-kind was built in 1938 in CMStP&P's own shops in Milwaukee, WI. This was also a Class S-1 and was given road number 251. At this time number 9700 was renumbered 250.

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.

Roster by Richard Duley

Class Road Numbers Year Built Builder
S-1 250 (ex 9700) 1930 Baldwin
S-1 251 1938 CMStP&P
S-2 201-230 1937 Baldwin
S-2 231-240 1940 Baldwin
S-3 260-269 1943 ALCO

Class Details by Steve Llanso

Class S1 (Locobase 247)

Data from 1930 Locomotive Cyclopedia tables. Also see Steve Glischinski's article on the MIlwaukee's generations of 4-8-4s at http://www.261.com/history/generations.shtml, last accessed 23 September 2007.

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.)

Class S2 - circulator (Locobase 248)

Data from 1947 Locomotive Cyclopedia table and diagram and from MILWRD 1945 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection. (Thanks to Chris Hohl for a correction of the boiler pressure.) Works numbers were 62092 in October 1937 and 62344, 62346 in March 1940; 62345, 62347 in April; 62348-62353 in May.

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.

Retired 1953-1956.

Class S2 - thermic syphon (Locobase 11085)

Data from MILWRD 1945 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection. . Works numbers were works numbers 62089-62091 in October 1937, 62093-62095 in November, 62096-62102 in December, 62103-62110 in January, 62111-62116 in February, and 62117 in March.

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.

Retired 1953-1956.

Class S3 (Locobase 249)

Data from 1947 Locomotive Cyclopedia tables. Also see Steve Glischinski's article on the MIlwaukee's generations of 4-8-4s at 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
Locobase ID 247 248 11085 249
Railroad Milwaukee Road (CMStP&P) Milwaukee Road (CMStP&P) Milwaukee Road (CMStP&P) Milwaukee Road (CMStP&P)
Whyte 4-8-4 4-8-4 4-8-4 4-8-4
Road Numbers 970 / 250-251 203, 231-240 201-202, 204-230 260-269
Gauge Std Std Std Std
Builder several Baldwin Baldwin Alco
Year 1930 1940 1937 1944
Valve Gear Baker Walschaert Walschaert Walschaert
Locomotive Length and Weight
Driver Wheelbase 19.75' 19.25' 19.25' 19.75'
Engine Wheelbase 46.25' 47.33' 47.33' 46.59'
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
Driver Diameter 74" 74" 74" 74"
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
Heating Ability
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
Power L1 39501 52146 52594 31278
Power MT 1345.88 1628.82 1642.81 1063.73

Photos

Reference

Credits

Introduction and roster provided by Richard Duley . Class details and specifications provided by Steve Llanso of Sweat House Media.

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