Santa Fe 2-10-10-2 Locomotives in the USA

The first 2-10-10-2s were constructed in 1911 by the Atchison, Topeka and Santa Fe Railroad at a cost of $43,880 each. They were built out of existing 900 & 1600 class 2-10-2s with new front engines and tenders from Baldwin. They were used between Bakersfield and Barstow and up to San Bernardino. The boilers could not sustain pressure and after ten years, the 10 locomotives were remanufactured into 20 3010 class 2-10-2s. The tenders survived intact for many years used behind some of the 2-10-2s.

Class Details by Steve Llanso of Sweat House Media

Class Santa Fe Mallet (Locobase 418)

Data from DeGolyer, Volume 37, pp. 277+. (Many thanks to Dan Watson for his 10 May 2016 email noting the 3001's movie role -it was a real treat to see this locomotive in action.)

Known as Santa Fe Mallets, these are among the few 2-10-10-2s built. Ten in number, the engines were cobbled together by the Santa Fe using existing 2-10-2 engine units united with low-pressure enginee units supplied by Baldwin. Baldwin also designed and built the unusual "turtleback" tender that probably was designed to improve rearward vision.

A distinctive ribbed firebox trailed the long boiler. Like other Santa Fe Mallets, the actual tube length was relatively short, but a "reheater" ahead of the forward tube sheet and boiler joint was supposed to maintain steam heat as it travelled forward to the HP cylinders. It added 2,659 sq ft, but was nowhere nearly as efficient as later superheater designs.

Overall, the design was unsuccessful and the engines were converted back to 2-10-2 simple-expansion locomotives in 1915-1918; see Locobase 5389.

But before they shucked their oddball dress, says Dan Watson's email of 10 May 2016, one of them got into the movies: "Regarding the AT&SF 3000 class 2-10-10-2 locomotives, the 3001 appeared in the theatrical film "The Hazards of Helen" Episode #3: "The Leap from the Water Tower" (1915) as available on youtube ..." Helen Holmes and Pearl White (of the Perils of Pauline) were widely known actresses whose serial jeopardy (including the literal cliffhangers that entered the language) for dozens of episodes. Locobase can recommend several of the Hazards episodes for the clear reproduction and fascinating railroading detail.

Specifications by Steve Llanso of Sweat House Media
ClassSanta Fe Mallet
Locobase ID418
RailroadSanta Fe (ATSF)
Number in Class10
Road Numbers3000-3009
Number Built10
BuilderSanta Fe
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)49.92 / 15.22
Engine Wheelbase (ft / m)66.42 / 20.24
Ratio of driving wheelbase to overall engine wheebase 0.75
Overall Wheelbase (engine & tender) (ft / m)108.10 / 32.95
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)550,000 / 249,476
Engine Weight (lbs / kg)616,000 / 279,413
Tender Loaded Weight (lbs / kg)266,450 / 120,860
Total Engine and Tender Weight (lbs / kg)882,450 / 400,273
Tender Water Capacity (gals / ML)13,000 / 49.24
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)12 / 10.90
Minimum weight of rail (calculated) (lb/yd / kg/m)92 / 46
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)57 / 1448
Boiler Pressure (psi / kPa)225 / 15.50
High Pressure Cylinders (dia x stroke) (in / mm)28" x 32" / 711x813
Low Pressure Cylinders (dia x stroke) (in / mm)38" x 32" / 965x813
Tractive Effort (lbs / kg)109,113 / 49492.88
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.04
Heating Ability
Firebox Area (sq ft / m2)284.50 / 26.44
Grate Area (sq ft / m2)81.90 / 7.61
Evaporative Heating Surface (sq ft / m2)3920 / 364.31
Superheating Surface (sq ft / m2)2380 / 221.19
Combined Heating Surface (sq ft / m2)6300 / 585.50
Evaporative Heating Surface/Cylinder Volume171.89
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation18,428
Same as above plus superheater percentage25,430
Same as above but substitute firebox area for grate area88,337
Power L113,619
Power MT545.90