These locomotives saw duty in both freight and passenger service. CB&Q was very pleased with the Class O-5 and after some modification to the design began building its own. Between 1936 and 1940 it built 28 Class O-5a Northerns (road numbers 5608 through 5635) in its own shops in W. Burlington, IA.
All 36 of these locomotives had 74" drivers, 28 x 30 cylinders, 250 psi boiler pressure, and had a traction effort of 67,500 lbs. The first eight weighed 461,000 lbs and the balance weighed 473,700 pounds.
There are four survivors: number 5614 on display in a city park in St. Joseph, MO; number 5629 at the Colorado Railroad Museum in Golden, CO; number 5631 at a depot in Sheridan, WY and number 5633 at the Douglass Railroad Interpretive Center which is located at the C&NW Depot in Douglass, WY.
|Class||Road Numbers||Year Built||Builder|
These engines were built in three batches, the first of which is shown in this entry:
O-5 5600-5607 by Baldwin in 1930 with Elesco K-50 feedwater heaters, Barco power reverse gear, DuPont Type B (modified) stoker, and Timken roller bearings on all but driving axles. The specs go into some interesting detail about the Baker valve motion: "Valve motion to have long travel, and designed to make loco[motive] snappy in starting and accelerating a heavy train." Locobase wonders how they knew if the locomotive was "snappy" enough. Later railfans describe the "bark" of the exhaust and how loud the engine was.
The first first six engines had fireboxes burning lignite coal, the last two took bituminous coal. The principal differences between them seems to have been grate, smokebox, and ashpan design. The two soft coal engines had standard-size 5/8" round holes while the lignite burners used "special design, i.e., with smaller [1/2"/12.7 mm] holes but more of them." Ashpans for the lignite users came with three hoppers and were to be designed "without regard to provision for booster." 5607 used a two-hopper, side-by-side layout to allow for a Franklin booster capable of 13,200 lb (5,987 kg) tractive effort. The Burlington supplied the Gillette netting used in lignite engine smokeboxes.
Firebox heating surface area included 83 sq ft (7.71 sq m) in the combustion chamber and 51 sq ft (4.74 sq m) in four arch tubes. Steam was admitted to the cylinders through 14" (356 mm) piston valves with 9" (279 mm) travel. Cylinders were cast integral with the locomotive bed. The boiler had four Ashton 3" (76 mm) safety valves, the muffled one set for the operating pressure of 250 psi. The other three "open" (i.e. not muffled, and therefore attention-gettingly loud) were set at 252, 254, and 256 psi.
Corbin & Kerka (1960) quote a fireman about the O-5's power: "They steamed best under a wide-open throttle, and on a light train one had to keep the reverse down in the corner." They report on one train of 82 mail cars worked by a single O-5 on 17 October 1944.
Five of the class--5600, 5602, 5604-5606--were fitted with Security circulators and reclassified O-5A. See Locobase 16137 for the O-5As produced by the Burlington itself.
Some were later converted to oil-burning. All retired in the mid-1950s.
Beginning six years after Baldwin's delivery of the first eight O-5 Northerns, the CB&Q built another 26 in its West Burlington shops. The engines used Baldwin boilers but Worthington SA feedwater heaters and none had trailing-truck boosters.
In the 1936 engines, the boiler now held only 51 2.25" tubes, but was otherwise essentially identical. Firebox heating surface included 45 sq ft (4.2 sq m) of arch tubes and 83 sq ft (7.7 sq m) of combustion chamber. All were fitted with Baker valve gear, Dupont stoker, 14"(356 mm) piston valves.
The last batch (O-5B) had one fewer 2 1/4" tube and 12 sq ft less heating surface area and Boxpok disc drivers. They also weighed about one short ton more.
Many of the earlier 4-8-4s were rebuilt to O-5A standard, which also included roller bearings, lightweight rods, vestibule cabs, and the solid pilot. Fireboxes in 5609-5610 were refitted with thermic syphons and 5618-5620 received security circulators.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Chicago, Burlington & Quincy (CB&Q)||Chicago, Burlington & Quincy (CB&Q)|
|Number in Class||8||28|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||19.25 / 5.87||19.25 / 5.87|
|Engine Wheelbase (ft / m)||45.50 / 13.87||45.50 / 13.87|
|Ratio of driving wheelbase to overall engine wheebase||0.42||0.42|
|Overall Wheelbase (engine & tender) (ft / m)||90.69 / 27.64||90.69 / 27.64|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)||69,340 / 31,452|
|Weight on Drivers (lbs / kg)||272,000 / 123,377||279,030 / 126,566|
|Engine Weight (lbs / kg)||454,600 / 206,203||474,620 / 215,284|
|Tender Loaded Weight (lbs / kg)||337,000 / 152,861||359,000 / 162,840|
|Total Engine and Tender Weight (lbs / kg)||791,600 / 359,064||833,620 / 378,124|
|Tender Water Capacity (gals / ML)||18,000 / 68.18||18,000 / 68.18|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||24 / 21.80||27 / 24.50|
|Minimum weight of rail (calculated) (lb/yd)||113||116|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||74 / 1880||74 / 1880|
|Boiler Pressure (psi / kPa)||250 / 17.20||250 / 17.20|
|High Pressure Cylinders (dia x stroke) (in / mm)||28" x 30" / 711x762||28" x 30" / 711x762|
|Tractive Effort (lbs / kg)||67,541 / 30636.12||67,541 / 30636.12|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.03||4.13|
|Firebox Area (sq ft / m2)||439 / 40.78||433 / 40.23|
|Grate Area (sq ft / m2)||106.50 / 9.89||106.50 / 9.89|
|Evaporative Heating Surface (sq ft / m2)||5317 / 493.96||5237 / 486.53|
|Superheating Surface (sq ft / m2)||2403 / 223.24||2403 / 223.24|
|Combined Heating Surface (sq ft / m2)||7720 / 717.20||7640 / 709.77|
|Evaporative Heating Surface/Cylinder Volume||248.69||244.95|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||26,625||26,625|
|Same as above plus superheater percentage||34,879||34,879|
|Same as above but substitute firebox area for grate area||143,773||141,808|