Data from Record of Recent Construction #68 (Baldwin Locomotive Works, 1910), p.24-25. See also DeGolyer, Volume 33, pp. 177+. Works number was 33867 in October 1909.
Other than those of the Great Northern (Locobases 352 and 13536), Baldwin managed to sell only three more of this unequal wheel arrangement to two other railroads. Two went to the Southern (Locobase 293) while this lone engine was delivered to a Georgia subsidiary.
The specifications called for the engine to haul 2,000 short tons up a straight 1% grade and 1,700 short tons up 1 1/4% straight grade, both loads at 8-10 mph (12-16 kph). Baldwin reported that the engine was operating over 1 1/4% grades and developing 72,700 lb (32,976 kg) of tractive effort. It used a "reheater" in the smokebox (638 sq ft/59.27 sq m) to dry the steam before admitting it to the low-pressure cylinders. All four cylinders were supplied through piston valves.
Locobase notes a considerable difference in heating surface areas from two sources. One is the tube heating surface as derived by subtracting the direct heating surface area from the evaporative heating surface area shown in Record #68. The other is calculated by finding the area of 437 2 1/4" tubes, each 21 feet long. This figure combined with the same direct heating surface area comes to 6,513 sq ft (605.08 sq m).
Here is a plausible, but as yet unproven, explanation. The original specification in Volume 33 of the DeGolyer collection includes a requirement that the tube's wall thickness be Birmingham Wire Gauge #11, which equates to .12" or 3.05 mm.
So what? Here's what: Almost all North American steam locomotive builders and operators used the outer diameter (aka "water side") to calculate the tubes' combined surface area. But many Continental railways and a select number of locomotive designers believed the more accurate measure of heat transfer should be based on the internal ("fire side") diameter. (Locobase won't recite the full debate here.)
When Locobase compares the two EHSs mentioned above, he finds a difference almost exactly the same as the difference between the results of using the tubes' internal or external diameters. It may be a coincidence, but the only articulateds to show this disparity were the AGS, two identical Southern Railway 2-6-8-0s,
Comparing the original specs in the DeGolyer volume with the data presented in the Record of Recent Construction shows the original weight estimates were a bit high, but the tender's loaded weight estimate only slightly on the low side.
After about four years of what must have been unsatisfying operation, the engine went over to the Chicago, New Orleans & Texas in 1914 for three years and then to the Southern itself. The Southern ran it for another eighteen years before scrapping it in 1935.
Data from CNO&TP MB 1917 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 35, pp. 95+.; and "Baldwin Mallet Articulated Compound for the Southern Railway", Railway and Locomotive Engineering, Volume 24, No. 6 (June 1911), p. 246. (Thanks to Chris Hohl for his 9 April 2018 email noting a discrepancy in the tender weight.) Works numbers were 36031-36032
Early Mallets with unequal wheel arrangement and a firebox that resembled a Wootten anthracite burner in its width. Rigid wheelbases were 10 ft (front) and 15 ft (rear). The smokebox held a Baldwin reheater (638 sq ft/59.27 sq m) to dry the steam before admitting it to the low-pressure cylinders.The HP cylinders were supplied by 13" (331 mm) piston valves; LP cylinders used Richardson balanced slide valves.
Only three built for the Southern (2) and Alabama Great Southern (see Locobase 10990).
Locobase notes a considerable difference in heating surface areas from two sources. One is the tube heating surface as derived by subtracting the direct heating surface area from the evaporative heating surface area shown in Record #68. The other is calculated by finding the area of 437 2 1/4" tubes, each 21 feet long. This figure combined with the same direct heating surface area comes to 6,513 sq ft (605.08 sq m).
Here is a plausible, but as yet unproven, explanation. The original specification in Volume 33 of the DeGolyer collection includes a requirement that the tube's wall thickness be Birmingham Wire Gauge #11, which equates to .12" or 3.05 mm.
So what? Here's what: Almost all North American steam locomotive builders and operators used the outer diameter (aka "water side") to calculate the tubes' combined surface area. But many Continental railways and a select number of locomotive designers believed the more accurate measure of heat transfer should be based on the internal ("fire side") diameter. (Locobase won't recite the full debate here.)
When Locobase compares the two EHSs mentioned above, he finds a difference almost exactly the same as the difference between the results of using the tubes' internal or external diameters. It may be a coincidence, but the only articulateds to show this disparity were the AGS, two identical Southern Railway 2-6-8-0s,
Boiler pressure later reduced and tractive effort dropped to 72,500 lb. Great Northern 2-6-8-0s were very similar.
Principal Dimensions by Steve Llanso of Middle Run Media | ||
---|---|---|
Class | J | Ls |
Locobase ID | 10990 | 293 |
Railroad | Alabama Great Southern (SRS) | Southern (SRS) |
Country | USA | USA |
Whyte | 2-6-8-0 | 2-6-8-0 |
Number in Class | 1 | 2 |
Road Numbers | 300/6399 | 4002-4003 |
Gauge | Std | Std |
Number Built | 1 | 2 |
Builder | Baldwin | Baldwin |
Year | 1909 | 1911 |
Valve Gear | Walschaert | Walschaert |
Locomotive Length and Weight | ||
Driver Wheelbase (ft / m) | 25 / 7.62 | 26 / 7.92 |
Engine Wheelbase (ft / m) | 43.33 / 13.21 | 43.33 / 13.21 |
Ratio of driving wheelbase to overall engine wheelbase | 0.58 | 0.60 |
Overall Wheelbase (engine & tender) (ft / m) | 71.54 / 21.81 | 71.54 / 21.81 |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | ||
Weight on Drivers (lbs / kg) | 332,700 / 150,910 | 332,700 / 150,910 |
Engine Weight (lbs / kg) | 363,550 / 164,904 | 363,500 / 164,881 |
Tender Loaded Weight (lbs / kg) | 171,450 / 77,769 | 171,450 / 77,769 |
Total Engine and Tender Weight (lbs / kg) | 535,000 / 242,673 | 534,950 / 242,650 |
Tender Water Capacity (gals / ML) | 9000 / 34.09 | 9000 / 34.09 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 13 / 12 | 13 / 12 |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 79 / 39.50 | 79 / 39.50 |
Geometry Relating to Tractive Effort | ||
Driver Diameter (in / mm) | 56 / 1422 | 56 / 1422 |
Boiler Pressure (psi / kPa) | 200 / 1380 | 200 / 1380 |
High Pressure Cylinders (dia x stroke) (in / mm) | 23" x 32" / 584x813 | 23" x 32" / 584x813 |
Low Pressure Cylinders (dia x stroke) (in / mm) | 35" x 32" / 889x813 | 35" x 32" / 889x813 |
Tractive Effort (lbs / kg) | 71,780 / 32558.90 | 71,780 / 32558.90 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.63 | 4.63 |
Heating Ability | ||
Tubes (number - dia) (in / mm) | 437 - 2.25" / 51 | 437 - 2.25" / 57 |
Flues (number - dia) (in / mm) | 32 - 5" / 127 | 32 - 5" / 127 |
Flue/Tube length (ft / m) | 21 / 6.40 | 21 / 6.40 |
Firebox Area (sq ft / m2) | 228 / 21.18 | 221 / 20.53 |
Grate Area (sq ft / m2) | 78 / 7.25 | 78 / 7.25 |
Evaporative Heating Surface (sq ft / m2) | 5611 / 521.47 | 5601 / 520.54 |
Superheating Surface (sq ft / m2) | ||
Combined Heating Surface (sq ft / m2) | 5611 / 521.47 | 5601 / 520.54 |
Evaporative Heating Surface/Cylinder Volume | 364.68 | 364.03 |
Computations Relating to Power Output (More Information) | ||
Robert LeMassena's Power Computation | 15,600 | 15,600 |
Same as above plus superheater percentage | 15,600 | 15,600 |
Same as above but substitute firebox area for grate area | 45,600 | 44,200 |
Power L1 | 3536 | 3513 |
Power MT | 164.02 | 162.95 |