Chicago, Burlington & Quincy / Colorado & Southern 2-8-2 "Mikado" Locomotives in the USA

Chicago, Burlington & Quincy

The first "Mikado" type locomotives on the Chicago, Burlington & Quincy Railroad arrived in a big way in 1910. The Baldwin Locomotive Works delivered fifty of these 2-8-2 locomotives, which were needed to replace the famous Burlington Route "Prairies" (2-6-2s). These 2-8-2s were designated as Class O-1 and assigned road numbers 5000 through 5049. The following year ten more came from Baldwin with road numbers 5050 through 5059. The Class O-1 "Mikados" had 64" diameter drivers, 27" x 30" cylinders, and a 170 psi boiler pressure resulting in a tractive effort of 49,378 pound, which was almost 14,400 pounds more than the most powerful "Prairie". The locomotives weighed 288,140 pounds. The firebox was 230.4 square feet, the evaporative surface was 3,678 square feet and with the Emerson superheater the combined heating surface was 4,357 square feet. The piston valve had a 14" diameter. .

In 1912 and 1913, Baldwin delivered 100 more of the 2-8-2s. These locomotives were designated as Class O-2 and given road numbers 5200 through 5299. They had 64" diameter drivers, 28" x 32" cylinders, a 180 psi boiler pressure and they exerted 59,975 pounds of tractive effort and each weighed 310,780 pounds. The firebox was 288 square feet which included 34 square feet of arch tubes, the evaporative surface was 4,657 square feet and with the superheater the combined heating surface was 5,618 square feet. The piston valve had a 14" diameter.

In 1915, the railroad took delivery of twenty-five Baldwin-built 2-8-2s that were designated as Class O-3 which it would reorder 15 more for delivery in 1919. The Class O-3 locomotives carried road numbers 5300 through 5339. They had 64" diameter drivers, 28" x 32" cylinders, the first fifteen of them had a 180 psi boiler pressure and the balance of forty-five were delivered with a 200 psi boiler pressure. They exerted 59,975 pounds or 66,640 pounds of tractive effort depending on the boiler pressure and each weighed 315,400 pounds. The firebox was 385 square feet which included 35 square feet of arch tubes and 69 square foot combustion chamber, the evaporative surface was 4,461 square feet and with the superheater the combined heating surface was 5,467 square feet. . .

By 1915, the CB&Q had 220 "Mikados" on its roster or on order and still needed more motive power. It would purchase 148 more between 1915 and 1923 similar to the Class O-1s.from Baldwin. These locomotives were designated as Class O-1a.and assigned road numbers beginning with the 5060 and running through 5147 for those delivered by 1922. There were not enough numbered in the 5100 series for the last batch of sixty, which were delivered in 1923, so they were assigned road numbers 4940 through 4999. The Q-1A delivered by 1922, numbers 5060 through 5147 had 64" diameter drivers, 27" x 30" cylinders, a 180 psi boiler pressure and they exerted 52,283 pounds of tractive effort and each weighed 316,780 pounds. The firebox was 292 square feet which included a 59 square foot combustion chamber, the evaporative surface was 3,364 square feet and with the superheater the combined heating surface was 4,115 square feet. The piston valve had a 14" diameter. The group of sixty delivered in 1923, road numbers 4940 through 4999, had 64" diameter drivers, 27" x 30" cylinders, a 200 psi boiler pressure and they exerted 58,092 pounds of tractive effort and each weighed 278,600 pounds. The firebox was 325 square feet, the evaporative surface was 3,409 square feet and with the superheater the combined heating surface was 4,178 square feet and the piston valve had a 14" diameter

In 1919, the USRA allocated fifteen "Mikado-Heavy" type locomotives which were built by Baldwin and delivered in 1919. This group was designated as Class O-4 and give road numbers 5500 through 5514. They had 63" diameter drivers, 27" x 32" cylinders, a 190 psi boiler pressure, they exerted 59,800 pounds of tractive effort depending and each weighed 325,000 pounds. The firebox was 313 square feet, the evaporative surface was 4,291 square feet and with the superheater the combined heating surface was 5,284 square feet. . .

There are three surviving CB&Q 2-8-2 "Mikado" type locomotives. They are numbers 4960, 4963 and 4978, all Class O-1A. Number 4960 is operational and is on the Grand Canyon Railway in Williams, AZ. Number 4963 is on display at the Illinois Railway Museum in Union, IL. Number 4978 is on display at the Union Depot Railroad Museum in Mendota, IL.

Colorado & Southern

The Colorado & Southern Railway Company was chartered in 1898, and operated in Wyoming, Colorado, and New Mexico. The company was formed when the Colorado & Southern acquired the Union Pacific, Denver and Gulf Railway and the Denver, Leadville and Gunnison Railway, both were subsidiaries of the Union Pacific. In Texas, the Colorado and Southern controlled a rail system extending from Texline, TX to Fort Worth and Dallas then to Houston and Galveston. The Colorado & Southern Railway operated independently from 1898 to 1908, then as part of the Chicago, Burlington and Quincy Railroad until it was absorbed into the Burlington Northern Railroad in 1981.

The Colorado & Southern Railway made one purchase of new "Mikado" type locomotives. It bought five from the Baldwin Locomotive Works in 1911. They were assigned road numbers 800 through 804. These locomotives had 57" diameter drivers, 26.5" x 30" cylinders, a 170 psi boiler pressure, they exerted 53,408 pounds of tractive effort and each weighed 283,340 pounds. The firebox was 254 square feet and the evaporative heating surface was 3,657 square feet. Later, they were upgraded with superheaters, the boiler pressure was increased to 200 psi, and Elesco feedwater heaters were added.

In 1957, six second-hand "Mikados' were bought from the CB&Q. These locomotives were given road numbers 804 through 809. The first number 804 was scrapped in 1954.

There are no surviving C&S 2-8-2 "Mikado" type locomotives.


Roster

Chicago, Burlington & Quincy

ClassQtyRoad NumbersYear BuiltBuilderNotes
O-1505000-50491910Baldwin1
O-1105050-50591911Baldwin2
O-2855200-52841912Baldwin3
O-2155285-52991913Baldwin4
O-3155300-53141915Baldwin5
O-3255315-53391917Baldwin6
O-1A155060-50741917Baldwin7
O-1A265075-51001918Baldwin8
O-3205340-53591919Baldwin9
O-4155500-55141919Baldwin10
O-1A75101-51071920Baldwin11
O-1A95108-51161921Baldwin12
O-1A315117-51471922Baldwin13
O-1A604940-49991923Baldwin14
Notes:
  1. Numbers 5000-5049 scrapped as follows: 5008 in 1927, 5017 & 5033 in 1947, 5023 in 1950 5006, 5022, 5036, 5045 and 5049 in 1951. The balance scrapped by the late 1950s.
  2. Numbers 5050-5059 scrapped as follows: 5051 & 5053 in 1933, 5055 & 5059 in 1950. The balance scrapped by the late 1950s.
  3. Numbers 5200-5284 scrapped between 1951 and 1954.
  4. Numbers 5285-5299 scrapped between 1951 and 1954.
  5. Numbers 5300-5414 scrapped between 1951 and 1956.
  6. Numbers 5415-5339 scrapped between 1951 and 1956.
  7. Numbers 5060-5074 scrapped between 1953 and 1957.
  8. Numbers 5075-5100 scrapped between 1953 and 1957.
  9. Numbers 5340-5359 scrapped between 1951 and 1956.
  10. Numbers 5500-5514 USRA allocated "Mikado-Heavy" locomotives. All scrapped between 1954 and 1957
  11. Numbers 5101-5107 scrapped between 1953 and 1957.
  12. Numbers 5108-5116 scrapped between 1953 and 1957.
  13. Numbers 5117-5137 scrapped between 1953 and 1957.
  14. Numbers 4940-4999 scrapped between 1951 and 1957 except numbers 4960, 4963 and 4978 which are preserved.

Colorado & Southern

ClassQty.Road NumbersFrom Other RRYr.. AcquiredYear BuiltBuilderNotes
E-4A5800-8041911Baldwin1
O-46804(2)-809CB&Q19571919Baldwin2
Notes:
  1. Numbers 800-804. Number 804 scrapped in 1953. All other scrapped in 1959.
  2. Acquired from the CB&Q in 1957. All scrapped in 1960

Class Details by Steve Llanso of Sweat House Media

Class E-4 (Locobase 13666)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 35, p. 10 Works numbers were 35894-35898 in January 1911.

Almost identical to the CB&Q O-1 Mikes shown in Locobase 474 but fitted with 57" drivers. these were the only 2-8-2s to be bought by the C&S. These had 14" (356 mm) piston valves.

The Emerson superheater was not satisfactory and was soon replaced by a Schmidt setup. See Locobase 1339 for the later upgrade with Schmidt superheater and Elesco feedwater heaters.

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


Class E-4-A (Locobase 1339)

Data from C & S 7 -1939 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 35894-35898 in January 1911.

Locobase 13666 describes the original version as delivered in 1911 with an Emerson superheater. This entry describes the later upgrade with Schmidt superheater and Elesco feedwater heaters.

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


Class O-1 (Locobase 474)

Corbin & Kerka (1960, p. 111), confirmed and supplemented by CB&Q Assorted Steam Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 35, pp. 1+. Works numbers were 35609-35616 in November 1910; 35685-35688, 35735-35752 in December; 35874-35893 in January 1911; 36998-37002 in September; 37025-37029 in October

First CB&Q mikes, 60 of which were delivered in 1910-1911 with tapered boilers, inside-admission 14"(356 mm) piston valves, Emerson superheaters in 24 flues. Baldwin estimated superheater area as 845 sq ft (78.5 sq m), but the CB&Q calculated the area as shown above in the specs. Firebox heating surface area included 32.4 sq ft (3.01 sq m) of arch tubes.

According to Baldwin's "Hereafter" note in its specifications, the railroad complained on 19 April 1911 that the installed cylinder heads were breaking. "Hereafter," the note said,"back cylinder heads to be cast steel."

Among the first American locomotives to be delivered with superheaters, these engines would soon be dwarfed by their two-years-younger brothers shown in Locobase 2902.

Upgrades were confined to such appliances as a Worthington #3 feed water heater. But the Burlington retained the rarely used Emerson superheater until the end of their days.

With the exception of 5008 scrapped in September 1927 (wrecked?), two scrapped in 1933 (5051, 5053) and in 1934 (5017, 5033), operated the entire class until the late 1940s. Some held on a little longer with 5023 and 5059 being scrapped in August 1950; 5055 in September; 5036 in February 1951; 5006, 5022, 5049 in April; and 5045 in May.


Class O-1A - 1917 (5060) (Locobase 11020)

Data from Corbin & Kerka (1960) and from locomotive diagram published on Vernon Beck's website -- [] (accessed 22 March 2003). See also DeGolyer, Volume 56, pp. 21+ and 39+ and Volume 67, pp. 54; and "New Locomotives for the Burlington, Colorado and Southern, and the Ft. Worth and Denver", Railway and Locomotive Engineering, Volume XXVIII [28], No 8 (August 1915), pp.262-264. Works number were:

1917

March 45359-45360; April 45463, 45521-45523; May 45621, 45636, 45664; June 45702-45703, 45759-45761, 45792

1918

June 48725-48726, 48904, 48949, 48994, 49072-49073; July 49228-49229, 49301, 49358, 49409-49410; August 49543-49544. 49640, 49653-49654; October 50130, 50362; November 50677; December 50787, 50942, 50988-50989

1920

November 54137; December 54170-54175

1921

January 54290-54292, 54362-54367

1922

April 55352; May 55400-55404, 55380-55381, 55454-55462; July 55497-55503, 55533-55539

Improved O-1s delivered in two batches: 88 in 1917-1922 (5060-5147), 60 more in 1923 (4940-4999); the latter engines are shown in Locobase 10.

Unlike the O-1s (Locobase 474), these had outside-admission 14" (356 mm) piston valves. Equipped with wagon-top boiler with radially stayed fireboxes and a short combustion chamber that reduced tube length by 2 1/2 feet (762 mm). To accommodate ten more flues for an enlarged superheater installation, the boiler sacrificed 21 small tubes. At a later date, the boiler pressure was raised from 180 psi (12.4 bar) to 200 psi. Some of the O-1As adopted a taller forward sand dome and 5144 was delivered with Young radial valve gear.

Direct heating surface area included 59 sq ft (5.5 sq m) from the combustion chamber and 33 sq ft (3.07 sq m) from arch tubes. 5060-5115 used a horizontal-type coal pusher and 5116-5147 were fitted with a slope-sheet type.

Like all of the Burlington's Mikados, these operated well into the 1950s with a few evading the ferro-knacker until 1960.


Class O-1A - 1923 (4940) (Locobase 10)

Data from Corbin & Kerka (1960) and from locomotive diagram published on Vernon Beck's website -- [] (accessed 22 March 2003). See also DeGolyer, Volume 67, pp. 97+; "Grand Canyon 4960" on Martyn Banes's Modern Steam Locomotive website at [], last accessed 15 May 2021; "Grand Canyon Railway 4960" in Wikipedia, also last accessed 15 May 2021; and William Vantuono, "Steam Power Returns to Grand Canyon Railway", Railway Age (17 February 2021) . (Many thanks to Chris Hohl for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error. Hohl's 2 April 2021 email provided information about the Grand Canyon Railway's tender. ) Works numbers in 1923 were:

May 56572-56576

July 56704-56713; 56804-56818

August 56931-56932, 56968-56972

September 56973-56975, 57073-57077, 57096, 57105-57114

October 57245-57248

This was the second order of Improved O-1s; the first 88 are described in Locobase 11020. 60 more in 1923 (4940-4999). Unlike the O-1s (Locobase 474), these had outside-admission 14" (356 mm) piston valves. The later group shown here were ten short tons (9,072 kg) heavier on the drivers and weighed 19 tons (17,237 kg) more overall.

The 4940s had a tapered boiler with Elesco or Worthington #3 feed water heater; boiler pressure raised from 170 psi (11.7 bar) to 200 psi. Radially stayed fireboxes were fitted with either B K or Martin stokers. The direct heating surface included 33 sq ft (3.05 sq m) of arch tubes and 59 sq ft of combustion chamber (5.48 sq m). Others had 58 sq ft (5.39 sq m) of thermic syphons instead of the arch tubes,

The 4960 later went on to serve the Grand Canyon Railway beginning in 1996 after age and wear in excursion service had led to a complete rebuilding.. Other changes included eight transverse arch tubes to increase water circulation and a smaller smokebox that Wikipedia reports led to a 30% decrease in back pressure. A 1999 custom-built injector delivered faster water flow. In 2005, the GCR replaced the original six-limbed Kiesel star nozzle with a Lempor exhaust that was reported to have worked well.

Wikipedia's entry said that the 1993 makeover meant the 4960 "has been so heavily modified, it now has an appearance of a 1940s era locomotive, instead of a 1920s locomotive it originally appeared as [sic]." Locobase thinks that OK because many locomotives were overhauled extensively, either because fads fade to be replaced by other fads or, more often, newer technology offers benefits deemed to be worth the cost..

Chris Hohl traced the 4960's tender history back to the Soo Lines' N-20 4-8-2 #4005 (Locobase 226). Tender number 4056 was modified by changing the fuel from 22 tons of coal to 3,600 US gallons (13,626 litres) of Waste Vegetable Oil (WVO). Railway Age reported that the 4960 was nicknamed "The Green Machine" for its use of WVO, for the snow melt water in its boiler, which is jacketed in dark green to match the tender's color.


Class O-2 (Locobase 2902)

Corbin & Kerka (1960, 114) and data from locomotive diagram published on Vernon Beck's website -- [] (accessed 22 March 2003). See also "Mikado Locomotives for the Burlington," Railway Age Gazette, Volume 53, No 22 (29 November 1912), p. 1045; and DeGolyer, Volume 46, pp. 212+.

Works numbers were

1912

August 38176-38177, 38205-38210; September 38229-38231, 38285-38289, 38365-38370, 38387-38392; October 38428-38433, 38501-38516; November 38768-38771, 38874-38889; December 38929-38932, 38973-38983

1913

January 39040-39041, 39071-39083.

Following closely on the heels of the O-1s (Locobase 474), the 100 O-2 Mikados had substantially larger, straight-top boilers and grates. The latter's firebox heating surface included 34 sq ft (3.15 sq m) of arch tubes. They were designed for "long, hard freight runs", according to the AERJ account, and were supplied with 14" (356 mm) piston valves with 1/4" (6.35 mm) lead, Ragonnet power reverse. All drivers were flanged, but provided with sufficient lateral play so as to negotiate 20-deg curves.

43 O-2a and 12 O-2bs were rebuilt O-2s; see Locobase 9461. The other 45 were scrapped in the 1920s and 1930s.


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

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

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 (5.48 sq m) to the firebox heating surface. 43 O-2As had 34 sq ft (3.16 sq m) of arch tubes; 12 O-2Bs did not. Inside the boiler, 79 tubes were removed to make room for 15 more flues for the Schmidt 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 settling on the drivers 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 three more decades.


Class O-3 (Locobase 5441)

Data from table in May 1916 issue of Railway Mechanical Engineer (RME) and from locomotive diagram published on Vernon Beck's website -- [] (accessed 22 March 2003). See also DeGolyer, Volume 56, pp. 60+; and "New Locomotives for the Burlington, Colorado and Southern, and the Ft. Worth and Denver", Railway and Locomotive Engineering, Volume XXVIII [28], No 8 (August 1915), pp.262-264. Works numbers were

1915

June 42126-42131, 42145-42149, 42162-42165

1917

March 45361-45362; April 45525-45527; May 45577-45579, 45630, 45637, 45665-45667; June 45712-45713, 45756, 45762-45764, 45794-45796, 45831-45833

1919

February 51264, 51275-51276, 51347, 51446; March 51480-51481, 51519-51521, 51631; April 51665, 51709-51710, 51742-51743; May 51760

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 (6.4 sq m) in the combustion chamber and 35 sq ft (3.25 sq m) of arch tubes . The first 15 were delivered with a pressure set to 180 psi (12.4 bar). The later engines came pressed to 200 psi. Piston valves measuring 14" (356 mm) in diameter admitted steam to the cylinders.

Otherwise they were derived from the earlier O-2s (Locobase 2920), which in turn were later modified along lines very similar to those of the O-3.


Class O-4 (USRA) (Locobase 9462)

Data from CB&Q - 1953 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange;and DeGolyer, Volume 58, pp. 96+. Works numbers were 51552-51553, 51585-51588, 51613-51621 in March 1919.

Very simply, these were fifteen USRA Heavy Mikados that went into service with the Burlington. These government engines were a bit smaller than the other CB&Q Mikes and had slightly less cylinder volume as well. Firebox heating surface area included a short combustion chamber presenting 51 sq ft (4.74 sq m) and four arch tubes contributing 28 sq ft (2.60 sq m). 14" (356 mm) piston valves supplied steam to the cylinders.

Later additions featured either Du Pont or Duplex mechanical stokers and either Worthington or Elesco feed water heaters.

But very few operators of the USRA Heavy Mike threw theirs away in any sort of haste and the Burlington kept its stud in service until the mid-1950s.

Principal Dimensions by Steve Llanso of Sweat House Media
ClassE-4E-4-AO-1O-1A - 1917 (5060)O-1A - 1923 (4940)
Locobase ID13666 1339 474 11020 10
RailroadColorado & Southern (CB&Q)Colorado & Southern (CB&Q)Chicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)
CountryUSAUSAUSAUSAUSA
Whyte2-8-22-8-22-8-22-8-22-8-2
Number in Class55608860
Road Numbers800-804800-8045000-50595060-51474940-4999
GaugeStdStdStdStdStd
Number Built5608860
BuilderBaldwinC&SBaldwinBaldwinBaldwin
Year19111925191019171923
Valve GearWalschaertWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)16.75 / 5.1116.75 / 5.1116.75 / 5.1116.75 / 5.1116.75 / 5.11
Engine Wheelbase (ft / m)33.79 / 10.3033.79 / 10.3033.79 / 10.3033.79 / 10.3033.79 / 10.30
Ratio of driving wheelbase to overall engine wheelbase 0.50 0.50 0.50 0.50 0.50
Overall Wheelbase (engine & tender) (ft / m)65.98 / 20.1167.16 / 20.4766.23 / 20.1968.42 / 20.8570 / 21.34
Axle Loading (Maximum Weight per Axle) (lbs / kg)53,800 / 24,403
Weight on Drivers (lbs / kg)207,000 / 93,894224,470 / 101,818223,450 / 101,355211,300 / 95,844232,650 / 105,528
Engine Weight (lbs / kg)271,000 / 122,924283,340 / 128,521288,140 / 130,698278,600 / 126,371316,780 / 143,689
Tender Loaded Weight (lbs / kg)160,300 / 72,711160,300 / 72,711169,700 / 76,975193,400 / 87,725195,200 / 88,541
Total Engine and Tender Weight (lbs / kg)431,300 / 195,635443,640 / 201,232457,840 / 207,673472,000 / 214,096511,980 / 232,230
Tender Water Capacity (gals / ML)8200 / 31.067500 / 28.419200 / 34.8510,000 / 37.8810,000 / 37.88
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)13 / 1213 / 1213 / 1219 / 1719 / 17
Minimum weight of rail (calculated) (lb/yd / kg/m)86 / 4394 / 4793 / 46.5088 / 4497 / 48.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)57 / 144857 / 144864 / 162664 / 162664 / 1626
Boiler Pressure (psi / kPa)170 / 13.80200 / 13.80170 / 11.70180 / 12.40200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)27" x 30" / 686x76226.5" x 30" / 673x76227" x 30" / 686x76227" x 30" / 686x76227" x 30" / 686x762
Tractive Effort (lbs / kg)55,442 / 25148.1062,833 / 28500.6049,378 / 22397.5152,283 / 23715.2058,092 / 26350.12
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.73 3.57 4.53 4.04 4.00
Heating Ability
Tubes (number - dia) (in / mm)221 - 2.25" / 57178 - 2.25" / 57221 - 2.25" / 57200 - 2.25" / 57200 - 2.25" / 57
Flues (number - dia) (in / mm)24 - 5.5" / 14040 - 5.5" / 14024 - 5.5" / 14034 - 5.5" / 14036 - 5.5" / 140
Flue/Tube length (ft / m)21 / 6.4021 / 6.4021 / 6.4018.50 / 5.6418.50 / 5.64
Firebox Area (sq ft / m2)215 / 19.97254 / 23.61232.40 / 21.59292 / 27.13325 / 30.19
Grate Area (sq ft / m2)54.20 / 5.0454.20 / 5.0454.20 / 5.0458.70 / 5.4558.80 / 5.46
Evaporative Heating Surface (sq ft / m2)3659 / 339.933657 / 339.873678 / 341.693364 / 312.523409 / 316.82
Superheating Surface (sq ft / m2)845 / 78.50993 / 92.29679 / 63.08769 / 71.44769 / 71.47
Combined Heating Surface (sq ft / m2)4504 / 418.434650 / 432.164357 / 404.774133 / 383.964178 / 388.29
Evaporative Heating Surface/Cylinder Volume184.05190.97185.01169.22171.48
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation921410,840921410,56611,760
Same as above plus superheater percentage10,96513,11610,68812,57413,877
Same as above but substitute firebox area for grate area43,49561,46845,82962,54676,700
Power L110,02413,755998911,34312,829
Power MT427.04540.38394.22473.39486.28

Principal Dimensions by Steve Llanso of Sweat House Media
ClassO-2O-2A/O-2BO-3O-4 (USRA)
Locobase ID2902 9461 5441 9462
RailroadChicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)Chicago, Burlington & Quincy (CB&Q)
CountryUSAUSAUSAUSA
Whyte2-8-22-8-22-8-22-8-2
Number in Class100556015
Road Numbers5200-52995200-52995300-53595500-5514
GaugeStdStdStdStd
Number Built1006015
BuilderBaldwinCB&QBaldwinBaldwin
Year1912192519151919
Valve GearWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)16.75 / 5.1116.75 / 5.1116.75 / 5.1116.75 / 5.11
Engine Wheelbase (ft / m)35.75 / 10.9035.75 / 10.9035.75 / 10.9036.08 / 11
Ratio of driving wheelbase to overall engine wheelbase 0.47 0.47 0.47 0.46
Overall Wheelbase (engine & tender) (ft / m)67.50 / 20.5768.41 / 20.8567.52 / 20.5867.12 / 20.46
Axle Loading (Maximum Weight per Axle) (lbs / kg)58,500 / 26,53565,270 / 29,60661,300 / 27,805
Weight on Drivers (lbs / kg)227,000 / 102,966248,710 / 112,813239,900 / 108,817239,000 / 108,409
Engine Weight (lbs / kg)310,780 / 140,968334,200 / 151,591315,400 / 143,063320,000 / 145,150
Tender Loaded Weight (lbs / kg)175,050 / 79,401175,050 / 79,401182,100 / 82,599183,650 / 83,302
Total Engine and Tender Weight (lbs / kg)485,830 / 220,369509,250 / 230,992497,500 / 225,662503,650 / 228,452
Tender Water Capacity (gals / ML)9200 / 34.859200 / 34.859200 / 34.8510,000 / 37.88
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)14 / 1314 / 1320 / 1816 / 15
Minimum weight of rail (calculated) (lb/yd / kg/m)95 / 47.50104 / 52100 / 50100 / 50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)64 / 162664 / 162664 / 162663 / 1600
Boiler Pressure (psi / kPa)180 / 12.40200 / 13.80200 / 13.80200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)28" x 32" / 711x81328" x 32" / 711x81328" x 32" / 711x81327" x 32" / 686x813
Tractive Effort (lbs / kg)59,976 / 27204.6966,640 / 30227.4366,640 / 30227.4362,949 / 28553.22
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.78 3.73 3.60 3.80
Heating Ability
Tubes (number - dia) (in / mm)275 - 2.25" / 57198 - 2.25" / 57264 - 2.25" / 57247 - 2.25" / 57
Flues (number - dia) (in / mm)30 - 6" / 15245 - 5.5" / 14045 - 5.5" / 14045 - 5.5" / 140
Flue/Tube length (ft / m)21 / 6.4018.60 / 5.6718.60 / 5.6719 / 5.79
Firebox Area (sq ft / m2)288 / 26.76333.80 / 31.02385 / 35.77313 / 29.09
Grate Area (sq ft / m2)78 / 7.2578 / 7.2578 / 7.2570.30 / 6.53
Evaporative Heating Surface (sq ft / m2)4657 / 432.653693 / 343.224461 / 414.444291 / 398.79
Superheating Surface (sq ft / m2)961 / 89.281031 / 95.821006 / 93.46993 / 92.29
Combined Heating Surface (sq ft / m2)5618 / 521.934724 / 439.045467 / 507.905284 / 491.08
Evaporative Heating Surface/Cylinder Volume204.16161.90195.57202.31
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation14,04015,60015,60014,060
Same as above plus superheater percentage16,42719,03218,40816,731
Same as above but substitute firebox area for grate area60,65381,44790,86074,494
Power L112,41213,69314,44014,647
Power MT482.18485.51530.80540.44

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