The Chicago, Burlington & Quincy Railroad bought eight 4-8-4 Northerns from the Baldwin Locomotive Works in 1930. They were designated Class O-5 and given road numbers 5600 through 5607.
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|
Data from DeGolyer, Volume 81, pp. 358+, CB&Q Steam Locomotive Diagrams Vernon Beck Collection supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange, "4-6-4 and 4-8-4 Type Power for the CB&Q", Railway Age, Volume 90, No 10 (7 March 1931), pp. 499-500; and tables in 1947 Locomotive Cyclopedia. (Thanks to Chuck Zeiler for his 28 July 2015 email correcting the original building year for the first batch of O-5s. Also, thanks to Chris Hohl for his 25 February 2020 email correcting Locobase's specs to reflect the lone builder, class ID and road number range for this octet.). Works numbers were 61443-61444 in August 1930, 61496-61499 in September, and 61522-61523 in October;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.
Data from DeGolyer, Volume 81, pp. 358+, CB&Q Steam Locomotive Diagrams Vernon Beck Collection supplied in August 2013 by Allen Stanley from his extensive Rail Data Exchange, and tables in 1947 Locomotive Cyclopedia. (Thanks to Chuck Zeiler for his 28 July 2015 email correcting the original building year for the first batch of O-5s, Also, Chris Hohl's 25 February 2020 email reported the conversion of O-5As to oil-burning O-5Bs, noting the difference in overall wheelbase, and reporting the numbers of the engines using either syphons (1) or circulators (4); see below.)Production dates were 5608-5609 in September 1936, 5610 in October, 5611-5612 in June 1937, 5613-5614 in July, 5615-5616 in August, 5617 in September, and 5618-5620 in October, 5621 in July 1938, 5622-5623 in August, 5624 in September, 5625 in October, 5626-5627 in April 1940, 5628 in May, 5629-5630 in June, 5631 in July, 5632-5633 in August, 5634 in September, and 5635 in October. 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. Timken roller bearings were fitted to all engine and tender axles and to the Baker-Pilliod valve gear. 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. At least four--5609, 5618-5620--were fitted with Security circulators and 5610 received thermic syphons. 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 and later 5609 received security circulators. Chris Hohl wrote to Locobase to add that "six of the CB&Q's O-5A/O-5B class 4-8-4s were converted to oil-burning and reclassified O-5B. The locomotives in question are #5614, 5620, 5626-5627, 5629, & 5632, and their tenders carried 7,300 US gallons (27,631 litres) of oil. With the new tenders, Hohl added, the total engine and tender wheelbase was 94 ft 1/8" (28.65 m).
|Principal Dimensions 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 wheelbase||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 / Liters/MT)||24 / 22||27 / 25|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||113 / 56.50||116 / 58|
|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|
|Tubes (number - dia) (in / mm)||57 - 2.25" / 57||51 - 2.25" / 57|
|Flues (number - dia) (in / mm)||218 - 3.5" / 89||218 - 3.5" / 89|
|Flue/Tube length (ft / m)||21 / 6.40||21 / 6.40|
|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|