Chicago, Burlington & Quincy / Colorado & Southern 2-8-2 "Mikado" Type Locomotives

Class E-4-A (Locobase 1339)

Data from C & S 7 -1939 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

Almost identical to the CB&Q O-1 Mikes shown in Locobase 474, but fitted with 57" drivers. Works numbers were 35894-35898. Data reflects later upgrades with superheater, 200-psi boiler pressure, and Elesco feedwater heaters.

Leased to the Burlington from 1933-1947, retired in 1960.

Class O-1 (Locobase 474)

First CB&Q mikes, 60 of which were delivered in 1910-1911 with tapered boilers, inside-admission piston valves, Emerson superheaters.

Corbin & Kerka (1960, p. 111)

Class O-1A (Locobase 10)

Improved O-1s delivered in two batches: 88 in 1917-1922 (5060-5147), 60 more in 1923 (4940-4999). Unlike the O-1s, these had outside-admission piston valves. Equipped with tapered boiler, radially stayed fireboxes whose heating surface included 33 sq ft of arch tubes and 59 sq ft of combustion chamber, feedwater heater; boiler pressure raised from 170 psi to 200 psi..

Corbin & Kerka (1960) and data from locomotive diagram published on Vernon Beck's website -- http://home.earthlink.net/~vnlbeck/T/T3t.tif (accessed 22 March 2003).

The 4960 later went on to serve the Grand Canyon Railway beginning in 1997. In 2005, it was fitted with a Lempor exhaust that was reported to have worked well.

Class O-2 (Locobase 2902)

Following closely on the heels of the O-1s, the 100 O-2 Mikados had larger, straight-top boilers and grates,

O-2As were rebuilt O-2s; see Locobase 9461.

Corbin & Kerka (1960, 114) and data from locomotive diagram published on Vernon Beck's website -- http://home.earthlink.net/~vnlbeck/T/T3t.tif (accessed 22 March 2003).

Class O-2A/O-2B (Locobase 9461)

Data from CB&Q - 1953 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

Locobase 2902 shows the O-2 class it entered service in 1912. When the Burlington remade this large class of Mikados in the middle 1920s, it didn't take half-measures. In addition to a new frame, new cylinders, Ragonnet power reverse, Duplex or DuPont stoker and other frills, the shops reworked the boiler. They introduced a combustion chamber that added 59 sq ft to the firebox heating surface. 43 O-2As had 34 sq ft of arch tubes; 12 O-2Bs did not. nside the boiler, 79 tubes were removed to make room for 15 more flues for the superheater. Each tube was shorter by the length of the combustion chamber.

The consequent heating surface area was considerably less, but the superheater ratio climbed to well over 20% of the total. All of the changes netted 12 tons of additional weight for the engine, much of it falling as increased adhesion weight.

All in all, a worthy set of alterations that stood the O-2 and the Burlington in good stead for almost 3 more decades.

Class O-3 (Locobase 5441)

The O-3s were the first Chicago, Burlington & Quincy Mikes delivered with a combustion chamber, brick arch and Schmidt superheater. The firebox heating surface included 69 sq ft in the combustion chamber and 35 sq ft of arch tubes. The first 15 were delivered with a pressure set to 180 psi. The later engines came pressed to 200 psi.

Otherwise they were derived from the earlier O-2s, which in turn were later modified along lines very similar to those of the O-3.

Data from table in May 1916 issue of Railway Mechanical Engineer (RME) and from locomotive diagram published on Vernon Beck's website -- http://home.earthlink.net/~vnlbeck/O/O3.tif (accessed 22 March 2003).

Class O-4 (Locobase 9462)

Data from CB&Q - 1953 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

Very simply, these were 15 USRA Heavy Mikados that went into service with the Burlington. Thee government engines were a bit smaller than the other CB & Q Mikes and had slightly less cylinder volume as well. But very few operators of the USRA Heavy Mike threw theirs away in any haste and the Burlington kept its stud in service until the mid-1950s.

Specifications
ClassE-4-AO-1O-1AO-2O-2A/O-2BO-3O-4
Locobase ID1339474102902946154419462
RailroadColorado & Southern (CB&Q)Chicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)
Whyte2-8-22-8-22-8-22-8-22-8-22-8-22-8-2
Road Numbers804-8095000-50595060-5147, 4940-49995200-52995200-52995300-53595500-5514
GaugeStdStdStdStdStdStdStd
BuilderBaldwinBaldwinBaldwinBaldwinCB&QBaldwinBaldwin
Year1911191019171912192519151919
Valve GearWalschaertWalschaertWalschaertWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase16.75'16.75'16.75'16.75'16.75'16.75'16.75'
Engine Wheelbase33.79'33.79'33.79'35.75'35.75'35.75'36.08'
Ratio of driving wheelbase to overall engine wheebase 0.50 0.50 0.50 0.47 0.47 0.47 0.46
Overall Wheelbase (engine & tender)67.16'66.23'70'67.50'68.41'67.52'67.12'
Axle Loading (Maximum Weight per Axle)53800 lbs58500 lbs65270 lbs61300 lbs
Weight on Drivers224470 lbs223450 lbs232650 lbs227000 lbs248710 lbs239900 lbs239000 lbs
Engine Weight283340 lbs288140 lbs316780 lbs310780 lbs334200 lbs315400 lbs320000 lbs
Tender Light Weight160300 lbs169700 lbs195200 lbs175050 lbs175050 lbs182100 lbs183650 lbs
Total Engine and Tender Weight443640 lbs457840 lbs511980 lbs485830 lbs509250 lbs497500 lbs503650 lbs
Tender Water Capacity7500 gals9200 gals10000 gals9200 gals9200 gals9200 gals10000 gals
Tender Fuel Capacity (oil/coal)13 tons13 tons19 tons14 tons14 tons20 tons16 tons
Minimum weight per yard of rail on which locomotive could run93.53 lb rail93.10 lb rail96.94 lb rail94.58 lb rail103.63 lb rail99.96 lb rail99.58 lb rail
Geometry Relating to Tractive Effort
Driver Diameter57"64"64"64"64"64"63"
Boiler Pressure200 psi170 psi200 psi180 psi200 psi200 psi200 psi
Cylinders (dia x stroke)26.5" x 30"27" x 30"27" x 30"28" x 32"28" x 32"28" x 32"27" x 32"
Tractive Effort62833 lbs49378 lbs58092 lbs59976 lbs66640 lbs66640 lbs62949 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.57 4.53 4.00 3.78 3.73 3.60 3.80
Heating Ability
Firebox Area254 sq. ft230.40 sq. ft346 sq. ft288 sq. ft333.80 sq. ft385 sq. ft313 sq. ft
Grate Area54.20 sq. ft54.20 sq. ft58.80 sq. ft78 sq. ft78 sq. ft78 sq. ft70.30 sq. ft
Evaporative Heating Surface3657367834094657369344614291
Superheating Surface99367976996110311006993
Combined Heating Surface4650435741785618472454675284
Evaporative Heating Surface/Cylinder Volume190.96185.01171.48204.20161.93195.61202.35
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1084092141176014040156001560014060
Same as above plus superheater percentage13154.8610649.9213924.5416441.6419004.6618470.6116702.24
Same as above but substitute firebox area for grate area61648.2645271.9981936.9160707.6181330.1991169.0174364.16
Power L113754.769979.5212941.4012414.6213695.8014443.2114649.47
Power MT540.37393.84490.54482.28485.61530.92540.53

Credits

Introduction and specifications provided by Steve Llanso of Sweat House Media.

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