Cotton Belt 2-8-0 "Consolidation" Locomotives of the USA


Class Details by Steve Llanso of Sweat House Media

Class G1 (Locobase 8474)

Data from StL&SW 1 - 1932 Folio 725 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also DeGolyer, Volume 30, p. 6 and Volume 32, p. 47. Joseph A Strapac, Cotton Belt Locomotives (Huntington, Calif: Shade Tree Books, 1977, reprinted in 1999 by Indiana University Press), p. 96. (Thanks to Chris Hohl for his 9 September 2016 email pointing out that most Cotton Belts engines were delivered as coal burners.) Works numbers were 29376-29377, 29407-29408, 29440-29441, 29447, 29497-29498, 29510 in November 1906.

Joe Strapac observed that "Despite their small size and unimpressive specifications", these engines began "...the fourth distinct generation of Cotton Belt motive power." They were delivered as coal-burners, as were most St Louis-Southwestern locomotives at the time. (By 1932, however, oil burners outnumbered coal burners by 3:1 in the locomotive diagram book referenced above.)

Strapac also noted that "[a]lthough Walschaerts [sic] valve gear was available, the 500-509 came with Stephenson link motion and slide valves and the almost inevitable spoked pilot wheels."

In the 1920s, the SSW superheated five of the locomotives in their original 2-8-0 layout; see Locobase 8475. Three more--504, 509, and 500--were converted to 0-8-0 switchers in 1928-1929. The other two, said Strapac, were to be converted as well and thus didn't receive the superheater upgrades, but the economic impacts of the Great Depression that began in late 1929 annulled those plans, leaving them essentially unchanged. 508 was scrapped in 1934 and 506 in 1937.


Class G1 - superheated (Locobase 8475)

Data from StL&SW 1 - 1932 Folio 725 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also Joseph A Strapac, Cotton Belt Locomotives (Huntington, Calif: Shade Tree Books, 1977, reprinted in 1999 by Indiana University Press), p. 96. (Thanks to Chris Hohl for his 9 September 2016 email commenting on valve gear that led to a review of this entry.)

Delivered in 1906 as saturated-steam locomotives (Locobase 8474), this class converted as shown beginning in 1925 (2), followed by 2 more in 1928, and the last to be modified in 1930.. The result is a powerful drag-freight locomotive with a decent level of superheat and relatively large 12" (305 mm) piston valves to deliver that dry steam to the cylinders. Moreover, unlike most such conversions, the total amount of heating surface remained almost the same.

Also unusual for conversions undertaken so late in the era, the shops dropped the boiler pressure. Since the increase in piston diameter meant no reduction in tractive effort, the designers might have seized an opportunity to reduce maintenance demands.

Note that 500, 504, and 509 also went through the boiler, cylinder, and valve gear upgrade, but lost their leading truck as part of a conversion in their role to heavy switching. They put substantially more weight on their drivers, increasing loaded weight to 213,000 lb (99,615 kg) and maximum axle loading to 55,900 lb (25,356 kg) and boiler pressure to 190 psi (13.1 bar) and thus tractive effort to 45,405 lb (20,595 kg or 201.97 kN).

At least one G1 (503) lost five tubes in order to accept a new firebox that was fitted with two Nicholson thermic syphons measuring a total of 43 sq ft. The result was a boiler with three more total sq ft of evaporative heating surface, but a firebox heating surface that had grown to 263 sq ft (24.45 sq m). The other four were equipped with brick arches.


Class G2 (Locobase 16158)

Data from StL&SW 1 - 1932 Folio 725 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also DeGolyer, Volume 30, p. 6 and Volume 32, p. 47. Joseph A Strapac, Cotton Belt Locomotives (Huntington, Calif: Shade Tree Books, 1977, reprinted in 1999 by Indiana University Press), p. 91. G2 works numbers were 33182-33186, 33203, 33220-33221, 33226-33227 in February 1909; 34805-34807, 34856-34859, 34870-34871 in June; 34912 in July; 34805-34807, 34856-34859, 34870-34871 in June 1910; 34912 in July.

These Consolidations were delivered in 1909-1910 as slightly modified variants of the G1s produced three years earlier (Locobase 8474). They had the same diameter cylinders, but a two-inch (50.8 mm) longer stroke.

Locobase describes the superheated G1s in its next entry ( Locobase 8475). The original saturated steamers formed this relatively lightweight class of Consolidations. Note that the design retained the narrow firebox between the drivers.


Class G2 - superheated (Locobase 8476)

Data from StL&SW 1 - 1932 Folio 725 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 33182-33186, 33203, 33220-33221, 33226-33227 in February 1909; 34805-34807, 34856-34859, 34870-34871 in June; and 34912 in July.

These Consolidations were delivered in 1909-1910 (Locobase 16158) as slightly modified variants of the G1s produced three years earlier (Locobase 8474). Like those engines, this class was soon superheated, the fitting of bigger cylinders being a relatively unusual change. The greater volume and slightly higher boiler pressure meant still more power for the grade. Capable of a substantial level of superheat and fitted with relatively large 12" (305 mm) piston valves to deliver that dry steam to the cylinders, these were even more powerful.

At least 3 G2 (510-11, 513) lost some 2" tubes in order to accept a new firebox that was fitted with two Nicholson thermic syphons measuring a total of 43 sq ft (4 sq m). The result was a boiler with 6 more total sq ft of evaporative heating surface, but a firebox heating surface that had grown to 280 sq ft(26.01 sq m).

524 & 526 were later converted to 0-8-0 switchers. Six were sold to the S P de M in Mexico in 1947 and the rest were retired between 1945 and 1953.


Class K-1 - 771 (Locobase 409)

Data from StL&SW 1 - 1945 Folio 725 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also DeGolyer, Vol 68, pp. 345+. Works numbers were 56513-56517, 56588-56597 in May 1923.

This last set of Consolidations continued the general line of 25"x 30" 2-8-0s that Baldwin supplied to the St Louis-Southwestern over a 10-year period. By now boiler pressure had crept to 200 psi, but many other characteristics were essentially unchanged. In the case of this 15-engine batch, however, there was a slight decrease in heating surface and in the 53 sq ft (4.9 sq m) of surface area contained in the two Nicholson thermic syphons that would be added soon after delivery. Piston valves measured 14" (356 mm) in diameter.

By the 1940s, the locomotives sported cross-balanced, disc drivers. Only the 764 failed to last until the 1950s; it suffered an explosion in December 1945. All of the others were sold for scrap between February 1952 and May 1956.


Class K1 (Locobase 8477)

Data from StL&SW 1 - 1932 Folio 725 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also "Ten-Wheeler Locomotive for the St Louis Southwestern", Railway and Locomotive Engineering, Volume 26, No. 9 (September 1913), pp. 312-313; and DeGolyer, Volume 48, pp. 69+ and pp. 81+. Works numbers were 38341-38344, 38353, 38393-8395 in September 1912; 38434-38437, 38517-38522 in October; 40059-40064 in June 1913; and 40158-40160, 40214 in July.

Baldwin began delivery of this large class in 1912. Compared to earlier StL-SW 2-8-0s, this class had wider grates but, surprisingly, less firebox heating surface. Also, it was equipped with 14" (356 mm) piston valves and Walschaert gear from the beginning. All in all, it was a scaled-up version of the G2 (Locobase 8476) in which the boiler's size compared to the cylinder volume remained about the same but the grate grew substantially.

Beginning in 1917, tweaks to the design created a variant deserving its own entry (Locobase 8478).


Class K1 - 61 (Locobase 8478)

Data from StL&SW 1 - 1932 Folio 725 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also DeGolyer, Volume 55, pp. 218+. Works numbers were 44572-44576, 44632-44634, and 44677-44680 in December 1916.

Although as delivered, these dozen Consolidations were appreciably different from the earlier K1s in only three minor respects: driver diameter, which grew by 2" (51 mm), driving wheelbase, which came a foot longer, and boiler pressure, which swelled by only 5 psi. They still had the same 14" (356 mm) piston valves, 29 sq ft (2.7 sq m) of arch tubes contributing to firebox heating surface, and the same boiler.

Locobase has chosen to document the three class members that were given two Nicholson thermic syphons each in place of the arch tubes. While they lost 15 sq ft (1.4 sq m) of arch tubes and 35 sq ft (3.25 sq m) in tube heating surface area, they gained 61 1/2 sq ft (5.7 sq m) in direct heating surface in a form that had been shown to convey significantly more heat to water per unit of area.


Class K1 - 750 (Locobase 8480)

Data from StL&SW 1 - 1945 Folio 725 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also DeGolyer, Vol 61, pp. 367+. Works numbers were 53483 in July 1920; 53532, 53561-53562 in August; 53620-53621, 53652-53653, 53690-53691 in September; 54240, 54377-54380, 54447, 54488-54492 in January 1921.

Baldwin added more K1 Consolidations after World War I that were virtually identical to those supplied before the Great War (Locobase 8478), although now they used Baker radial valve gear to actuate their 14"(356 mm) diameter piston valves. The original firebox had 214.6 sq ft (19.9 sq m), of which 28.6 sq ft (2.65 sq m) came from the arch tubes. By the 1940s, most of the class had been fitted with 62 sq ft of Nicholson thermic syphons (two) and this is represented in the specs.

See Locobase 409 for the 1923 Baldwins, which had some differences from this batch.

When the Cotton Belt began jettisoning its steam fleet, it found two principal buyers. The FerroCarril de Pacifico took twelve of the class (750, 752, 754, 756-757, 760-761, 763, 765-766, 769-770), most of which it scrapped in the mid-to-late 1950s. One -- 638 (ex-756) -- survived to be classed GR-52 by the Nacional de Mexico. The Espee took four as their class C-11 -- 751, 753, 755, 768 -- and renumbered them 2861-2864. 2863 was scrapped first in March 1960. The other 3 were broken up in April 1961.

Specifications by Steve Llanso of Sweat House Media
ClassG1G1 - superheatedG2G2 - superheatedK-1 - 771
Locobase ID8474 8475 16158 8476 409
RailroadCotton Belt (StLSW)Cotton Belt (StLSW)Cotton Belt (StLSW)Cotton Belt (StLSW)Cotton Belt (StLSW)
CountryUSAUSAUSAUSAUSA
Whyte2-8-02-8-02-8-02-8-02-8-0
Number in Class105202015
Road Numbers500-509501-503, 505, 507510-529510-529771-785
GaugeStdStdStdStdStd
Number Built102015
BuilderBaldwinCotton BeltBaldwinCotton BeltBaldwin
Year1906192519091923
Valve GearStephensonWalschaertStephensonWalschaertBaker
Locomotive Length and Weight
Driver Wheelbase16'16'16'16'17.50'
Engine Wheelbase24.50'24.50'24.50'24.50'26.50'
Ratio of driving wheelbase to overall engine wheebase 0.65 0.65 0.65 0.65 0.66
Overall Wheelbase (engine & tender)58.23'58.27'58.23'58.02'63.38'
Axle Loading (Maximum Weight per Axle)44500 lbs45250 lbs44500 lbs46250 lbs56895 lbs
Weight on Drivers169000 lbs178000 lbs173000 lbs182000 lbs213745 lbs
Engine Weight190000 lbs201000 lbs195000 lbs206000 lbs243775 lbs
Tender Light Weight158035 lbs154400 lbs164000 lbs195000 lbs
Total Engine and Tender Weight359035 lbs349400 lbs370000 lbs438775 lbs
Tender Water Capacity7000 gals7000 gals7000 gals7500 gals9000 gals
Tender Fuel Capacity (oil/coal)3250 gals3250 gals3350 gals3500 gals
Minimum weight of rail (calculated)70 lb/yard74 lb/yard72 lb/yard76 lb/yard89 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter55"55"55"55"61"
Boiler Pressure200 psi175 psi200 psi180 psi200 psi
Cylinders (dia x stroke)22" x 28"23.5" x 28"22" x 30"23.5" x 30"25" x 30"
Tractive Effort41888 lbs41820 lbs44880 lbs46088 lbs52254 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.03 4.26 3.85 3.95 4.09
Heating Ability
Firebox Area224 sq. ft222 sq. ft224 sq. ft239 sq. ft239 sq. ft
Grate Area32.70 sq. ft32.70 sq. ft32.70 sq. ft32.70 sq. ft52.50 sq. ft
Evaporative Heating Surface2761 sq. ft2257 sq. ft2761 sq. ft2274 sq. ft2748 sq. ft
Superheating Surface530 sq. ft530 sq. ft591 sq. ft
Combined Heating Surface2761 sq. ft2787 sq. ft2761 sq. ft2804 sq. ft3339 sq. ft
Evaporative Heating Surface/Cylinder Volume224.12160.57209.18150.99161.23
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation654057236540588610500
Same as above plus superheater percentage654068106540700412390
Same as above but substitute firebox area for grate area4480046232448005119456404
Power L1577692865391902711049
Power MT301.39460.05274.80437.39455.85

Specifications by Steve Llanso of Sweat House Media
ClassK1K1 - 61K1 - 750
Locobase ID8477 8478 8480
RailroadCotton Belt (StLSW)Cotton Belt (StLSW)Cotton Belt (StLSW)
CountryUSAUSAUSA
Whyte2-8-02-8-02-8-0
Number in Class281235
Road Numbers550-577578-590750-770
GaugeStdStdStd
Number Built281235
BuilderBaldwinBaldwinBaldwin
Year191319161920
Valve GearWalschaertWalschaertBaker
Locomotive Length and Weight
Driver Wheelbase16.50'17.50'17.50'
Engine Wheelbase25.50'26.50'26.50'
Ratio of driving wheelbase to overall engine wheebase 0.65 0.66 0.66
Overall Wheelbase (engine & tender)62.69'62.85'63.67'
Axle Loading (Maximum Weight per Axle)53000 lbs53500 lbs54700 lbs
Weight on Drivers209000 lbs211000 lbs212300 lbs
Engine Weight239000 lbs243000 lbs243000 lbs
Tender Light Weight208000 lbs195000 lbs195000 lbs
Total Engine and Tender Weight447000 lbs438000 lbs438000 lbs
Tender Water Capacity9000 gals9000 gals9000 gals
Tender Fuel Capacity (oil/coal)3250 gals3500 gals3500 gals
Minimum weight of rail (calculated)87 lb/yard88 lb/yard88 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter57"61"61"
Boiler Pressure185 psi190 psi190 psi
Cylinders (dia x stroke)25" x 30"25" x 30"25" x 30"
Tractive Effort51727 lbs49641 lbs49641 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.04 4.25 4.28
Heating Ability
Firebox Area201 sq. ft243.50 sq. ft244 sq. ft
Grate Area52.50 sq. ft52.50 sq. ft52.50 sq. ft
Evaporative Heating Surface2786 sq. ft2751 sq. ft2751 sq. ft
Superheating Surface578 sq. ft591 sq. ft591 sq. ft
Combined Heating Surface3364 sq. ft3342 sq. ft3342 sq. ft
Evaporative Heating Surface/Cylinder Volume163.46161.40161.40
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation971399759975
Same as above plus superheater percentage113641177111771
Same as above but substitute firebox area for grate area435065459354705
Power L192731052610529
Power MT391.26439.92437.35


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