Pennsylvania 2-10-2 "Santa Fe" Type Locomotives

Class N1s (Locobase 82)

Baldwin (25) and Brooks (35) both built engines in this class that William D Edson (Keystone Steam & Electric, 1974) says were built to serve the Lines West requirement for heavy freight movement out of the Lake ports. One stringent requirement was the need to be able to negotiate 22-deg curves, accomplished by using flangeless center drivers and lateral-motion axle boxes on the front and rear driver set. Of course, if it's Pennsy, it must have a Belpaire boiler. See Locobase 32 for a comment on the unique design of Pennsy's Belpaire firebox.

The heating surface calculations are an estimate based on the total heating surface as revealed by Rob Schoenberg's diagram (http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=N1s-E65881.gif&sel=ste&sz=sm&fr=, visited December 2002), the number and diameter of the tubes and flues, and a subtraction of the calculated total of the tubes and flues from the total. The results fit Pennsy practice pretty closely.

Like most Pennsy steam, these locomotives operated into the late 1940s.

Class N2s (Locobase 1425)

Data from Rob Schoenberg's http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=N2sa-E85283.gif&sel=ste&sz=sm&fr= (visited December 2002), which reproduces the 1928 diagrams and thus the dimensions after reconstruction with the Belpaire firebox.

Firebox had combustion chamber. The more widely emulated of the two USRA "Santa Fe" designs. Delivered originally with radial-stay fireboxes, these engines received the typical Pennsy Belpaire-type firebox in 1923. See Locobase 32 for a comment on the unique design of Pennsy's Belpaire firebox.

Eugene Huddleston (Trains, March 1991), writing about this design, comments that the Pennsy found that when assigned trains in accordance with their tractive power, these engines "handled their tonnage in a satisfactory manner."

Specifications
Class	N1s	N2s
Locobase ID	82	1425
Railroad	Pennsylvania (PRR)	Pennsylvania (PRR)
Whyte	2-10-2	2-10-2
Road Numbers	7008+	7036+
Gauge	Std	Std
Builder	Several	Several
Year	1918	1919
Valve Gear	Walschaert	Southern
	Locomotive Length and Weight
Driver Wheelbase	22.17'	22.33'
Engine Wheelbase	41.96'	42.17'
Ratio of driving wheelbase to overall engine wheebase	0.53	0.53
Overall Wheelbase (engine & tender)	82.77'	82.87'
Axle Loading (Maximum Weight per Axle)	75600 lbs	63200 lbs
Weight on Drivers	351000 lbs	297000 lbs
Engine Weight	435000 lbs	380700 lbs
Tender Light Weight	206100 lbs	211200 lbs
Total Engine and Tender Weight	641100 lbs	591900 lbs
Tender Water Capacity	9600 gals	12000 gals
Tender Fuel Capacity (oil/coal)	19.7 tons	16.9 tons
Minimum weight per yard of rail on which locomotive could run	117 lb rail	99 lb rail
	Geometry Relating to Tractive Effort
Driver Diameter	62"	63"
Boiler Pressure	215 psi	190 psi
Cylinders (dia x stroke)	30" x 32"	30" x 32"
Tractive Effort	84890 lbs	73829 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort)	4.13	4.02
	Heating Ability
Firebox Area	422 sq. ft	420 sq. ft
Grate Area	79.90 sq. ft	83.20 sq. ft
Evaporative Heating Surface	4718	4980
Superheating Surface	1373	1222
Combined Heating Surface	6091	6202
Evaporative Heating Surface/Cylinder Volume	180.21	190.22
	Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation	17179	15808
Same as above plus superheater percentage	20614	18970
Same as above but substitute firebox area for grate area	108876	95760
Power L1	16281	13776
Power MT	511.30	511.29