These Class 4101 "Berkshires" had 63" diameter drivers, 27" x 32" cylinders, a boiler pressure of 220 psi with a resultant tractive effort of 69,200 pounds (number 4115 had a 250 psi boiler pressure, which raised its tractive effort to 78,685 lbs). Each of the fifteen locomotives weighed 393,000 pounds.
The AT&SF also bought seven used "Berkshire" type locomotives from the Boston & Maine during the closing months of World War II.
There are no surviving AT&SF 2-8-4 "Berkshire" type locomotives
|Class||Qty.||Road Numbers||Year Built||Builder||Notes|
Described by Drury (1993) as "basically good 1922 engines with a 1927 wheel arrangement." An assessment borne out by the tube-to-flue ratio and relatively meager supplementary heating surface areas. Boiler had Elesco H-5 feedwater heater and 44 sq ft (4.1 sq m) of arch tubes contributing to the direct heating surface. Steam was admitted through 15" (381 mm) piston valves.
4115 was delivered with a boiler designed to be pressed to 250 psi (17.25 bar) with a cutoff set to 68%. This combination of stroke length and boiler pressure yielded the same tractive effort as the others, but the piston load was calculated to increase by 15%. Other slight differences included a valve travel of 9 1/2" (241 mm), 1/2" (12.7 mm) longer than the valves in the others.
15 engines delivered in 1927, retired in 1954.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Santa Fe (ATSF)|
|Number in Class||15|
|Locomotive Length and Weight|
|Driver Wheelbase (ft)||16.50|
|Engine Wheelbase (ft)||37.20|
|Ratio of driving wheelbase to overall engine wheebase||0.44|
|Overall Wheelbase (engine & tender) (ft)||81.60|
|Axle Loading (Maximum Weight per Axle) (lbs)||70,480|
|Weight on Drivers (lbs)||268,200|
|Engine Weight (lbs)||396,500|
|Tender Loaded Weight (lbs)||285,100|
|Total Engine and Tender Weight (lbs)||681,600|
|Tender Water Capacity (gals)||15,000|
|Tender Fuel Capacity (oil/coal) (gals/tons)||20|
|Minimum weight of rail (calculated) (lb/yd)||112|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in)||63|
|Boiler Pressure (psi)||220|
|High Pressure Cylinders (dia x stroke) (in)||27" x 32"|
|Tractive Effort (lbs)||69,243|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||3.87|
|Firebox Area (sq ft)||338|
|Grate Area (sq ft)||99|
|Evaporative Heating Surface (sq ft)||4577|
|Superheating Surface (sq ft)||1246|
|Combined Heating Surface (sq ft)||5823|
|Evaporative Heating Surface/Cylinder Volume||215.84|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||21,780|
|Same as above plus superheater percentage||26,354|
|Same as above but substitute firebox area for grate area||89,976|