Chicago, Burlington & Quincy 4-6-4 "Hudson" Locomotives

The Chicago, Burlington & Quincy Railroad purchased twelve Hudsons from the Baldwin Locomotive Works in 1930. These 4-6-4's were designated Class S-4 and assigned road numbers 3000 through 3011. The CB&Q also built two Hudsons in its own shops and assigned them road numbers 3012 and 4001. There are five surviving CB&Q Hudsons and they are on display at locations in Iowa, Illinois and Wisconsin.

Class Details by Steve Llanso of Sweat House Media

Class S-4 (Locobase 181)

Corbin & Kerka (1960, p 106) and CB&Q 3 - 1953 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. (Thanks to Chris Hohl for pointing out the error in renumbering for the second Zephyr-style streamliner.) See also DeGolyer, Vol 81, pp. 329+. Works numbers were 61445-61446 in August 1930, 61500-61501 in September, 61525-61528 in October, and 61555-61558 in November.

Twelve by Baldwin, a thirteenth (S-4A) by the West Burlington shops using a Baldwin boiler. All but 4001 had Elesco feedwater heaters; 4001 had a Worthington. Other goodies included a Barco Type 4 power reverse gear, Type B stokers, and 14" diameter pistons. Firebox heating surface included 43 sq ft (4.0 sq m) of arch tubes and 70 sq ft (6.5 sq m) of combustion chamber.

Corbin & Kerka report that when these locomotives went into service pulling such trains as the Ak-Sar-Ben, the Aristocrat, and the Black Hawk, the Burlington was able to do away with swapping one locomotive for another during the trip. One is credited with hauling ten standard passenger cars between Cochrane and La Crosse (Wis) at 112 mph. The authors conclude "The 4-6-4 types were perhaps the some of the most successful locomotives used on the Chicago, Burlington & Quincy."

One (3002) was streamlined to resemble the stainless-steel Zephyrs, renumbered 4000 and called Aeolus and nicknamed "Big Alice the Goon." After her success, a second was built from scratch and numbered 4001.

The modification, dubbed S-4A, was more than cosmetic. They also received Box-Pok drivers and roller bearings in the lightweight side rods. Three more S-4s (3008, 3009, and 3011) received the running gear upgrades in 1938, but not the shrouds. They were renumbered 4003-4005.

Corbin & Kerka (1960); Railway Age 7 March 1931; and locomotive diagram published on Vernon Beck's website -- (accessed 22 March 2003)

Specifications by Steve Llanso of Sweat House Media
Class S-4
Locobase ID 181
Railroad Chicago, Burlington & Quincy (CB&Q)
Country USA
Whyte 4-6-4
Road Numbers 3000-3012
Gauge Std
Builder Baldwin
Year 1930
Valve Gear Baker
Locomotive Length and Weight
Driver Wheelbase 13.67'
Engine Wheelbase 39.92'
Ratio of driving wheelbase to overall engine wheebase 0.34
Overall Wheelbase (engine & tender) 82.23'
Axle Loading (Maximum Weight per Axle) 69780 lbs
Weight on Drivers 207730 lbs
Engine Weight 391880 lbs
Tender Light Weight 326050 lbs
Total Engine and Tender Weight 717930 lbs
Tender Water Capacity 15000 gals
Tender Fuel Capacity (oil/coal) 24 tons
Minimum weight of rail (calculated) 115 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter 78"
Boiler Pressure 250 psi
Cylinders (dia x stroke) 25" x 28"
Tractive Effort 47676 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.36
Heating Ability
Firebox Area 369 sq. ft
Grate Area 87.90 sq. ft
Evaporative Heating Surface 4247 sq. ft
Superheating Surface 1830 sq. ft
Combined Heating Surface 6077 sq. ft
Evaporative Heating Surface/Cylinder Volume 266.97
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation 21975
Same as above plus superheater percentage 28568
Same as above but substitute firebox area for grate area 119925
Power L1 46094
Power MT 1467.57



  • Steam Locomotives of the Burlington Route by Bernard Corbin and William Kerka, Published by Bernard Corbin and William Kerka
  • Burlington Route Historical Society
  • Railroads of Northern Colorado by Kenneth Jessen, Published by Pruett Publishing Company

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