This single Prairie Mallet was assembled out of two 2-6-2 Prairies (1051 & 1125). It was fitted with a superheater, a reheater, and a chamber to supply some heat to the exhausted steam from the HP cylinders before it was directed into the LP cylinders. The diagram shows the long profile with a joint made of plates that linked the two 2-6-2 boilers as well as the surprisingly high drivers.
In 1924, the 1051 was allowed to reclaim its identity as the 1157 was broken up.
When Baldwin began supplying its Prairie Mallets to the Santa Fe, the company sent the 20 rigid-boiler engines shown in Locobase . A few months later, the builder added 10 more that were for some reason given lower numbers. These were works #35617-
35620, 35680-35681, 35727-35730 and were produced in November 1910.
Known as "Prairie Mallets." 24 built altogether, 20 with rigid boilers. These operated until 1927-1934. Locobase is struck by the relatively tall drivers for a compound Mallet design.
Four others have a modest notoriety in articulated-locomotive design annals for their hinged boilers. The first version had a bellows arrangement of fifty (or sixty -- sources differ) 10-in wide rings bolted alternately. These tended to burst when cinders fouled them on curves. A later version included a ball-and-socket set-up. Neither worked very well.
Firebox heating surface included 32 sq ft of arch tubes. The boiler surface area describes only the tubes and firebox. It does not count the boiler preheater (1,550 sq ft) or the boiler-mounted superheater (986.4 sq ft).
Known as "Prairie Mallets." 24 built altogether, 20 with rigid boilers. These operated until 1927-1934.
Four others have a modest notoriety in articulated-locomotive design annals for their hinged boilers. The first version had a bellows arrangement of fifty (or sixty -- sources differ) 10-in wide rings bolted alternately. These tended to burst when cinders fouled them on curves. A later version included a ball-and-socket set-up. Neither worked very well.
| Specifications | ||||
|---|---|---|---|---|
| Class | 1157 | 1160-1169 | 1170-1197 | 3300 |
| Locobase ID | 9011 | 9012 | 3553 | 442 |
| Railroad | Santa Fe (ATSF) | Santa Fe (ATSF) | Santa Fe (ATSF) | Santa Fe (ATSF) |
| Whyte | 2-6-6-2 | 2-6-6-2 | 2-6-6-2 | 2-6-6-2 |
| Road Numbers | 1157 | 1160-1169 | 1170-1197 | 3300-3323 |
| Gauge | Std | Std | Std | Std |
| Builder | ATSF | Baldwin | Baldwin | Baldwin |
| Year | 1910 | 1910 | 1909 | 1911 |
| Valve Gear | Walschaert | Walschaert | Walschaert | Walschaert |
| Locomotive Length and Weight | ||||
| Driver Wheelbase | 13.67' | 13.67' | 37.83' | 37.83' |
| Engine Wheelbase | 57.25' | 57.25' | 56.41' | 56.41' |
| Ratio of driving wheelbase to overall engine wheebase | 0.24 | 0.24 | 0.67 | 0.67 |
| Overall Wheelbase (engine & tender) | 89.60' | 89.60' | 89.24' | 89.24' |
| Axle Loading (Maximum Weight per Axle) | 62900 lbs | |||
| Weight on Drivers | 304300 lbs | 304300 lbs | 319000 lbs | 329400 lbs |
| Engine Weight | 370200 lbs | 370200 lbs | 390200 lbs | 400800 lbs |
| Tender Light Weight | 164500 lbs | 164500 lbs | 174800 lbs | 185400 lbs |
| Total Engine and Tender Weight | 534700 lbs | 534700 lbs | 565000 lbs | 586200 lbs |
| Tender Water Capacity | 9000 gals | 9000 gals | 9000 gals | 9000 gals |
| Tender Fuel Capacity (oil/coal) | 14 tons | 14 tons | 12 tons | 12 tons |
| Minimum weight per yard of rail on which locomotive could run | 84.53 lb rail | 84.53 lb rail | 88.61 lb rail | 91.50 lb rail |
| Geometry Relating to Tractive Effort | ||||
| Driver Diameter | 69" | 69" | 69" | 70" |
| Boiler Pressure | 220 psi | 220 psi | 220 psi | 220 psi |
| Cylinders (dia x stroke) | 24" x 28" | 24" x 28" | 24" x 28" | 24" x 28" |
| Low Pressure Cylinders (dia x stroke) | 38" x 28" | 38" x 28" | 38" x 28" | 38" x 28" |
| Tractive Effort | 62491 lbs | 62491 lbs | 62491 lbs | 61598 lbs |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.87 | 4.87 | 5.10 | 5.35 |
| Heating Ability | ||||
| Firebox Area | 195 sq. ft | 222 sq. ft | 237 sq. ft | 245 sq. ft |
| Grate Area | 53.50 sq. ft | 54 sq. ft | 63.40 sq. ft | 63.40 sq. ft |
| Evaporative Heating Surface | 3942 | 5201 | 5176 | 3721 |
| Superheating Surface | 1063 | 970 | 955 | |
| Combined Heating Surface | 5005 | 6171 | 6131 | 3721 |
| Evaporative Heating Surface/Cylinder Volume | 268.88 | 354.76 | 353.05 | 253.81 |
| Computations Relating to Power Output (More Information) | ||||
| Robert LeMassena's Power Computation | 11770 | 11880 | 13948 | 13948 |
| Same as above plus superheater percentage | 14269.80 | 13747.38 | 16120.62 | 13948 |
| Same as above but substitute firebox area for grate area | 52011.43 | 56517.01 | 60261.63 | 53900 |
| Power L1 | 9970.29 | 10353.71 | 10295.20 | 3454.00 |
| Power MT | 433.40 | 450.07 | 426.90 | 138.70 |
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