Delaware, Lackawanna &Western 4-8-2 "Mountain" Type Locomotives

Class P-1 (Locobase 5731)

Data from set of DL&W locomotive diagrams at http://www.rr-fallenflags.org/el/loco/dlw-127.html (29 October 2003). See also Robert A LeMassena, "The USRA HEAVY 4-8-2 and its Illustrious Ascendants", Railway & Locomotive Historical Society Newsletter (Vol 23, #2 - Spring 2003).

Firebox heating surface included 35 sq ft of arch tubes. Drury (1993) says these 5 Mountains (the first on the line) were bought to eliminate double-heading passenger trains on the grades east of Scranton, PA. But they were soon relegated to local service because of their lack of speed.

When the Atlantic Coast Line found itself short of power in World War II, the Lackawanna realized it could spare this class. As the J-1s, these were put in service between Tampa, Fla and Albany, Ga until their retirement in 1951-1952.

Class P-2/P-3 (Locobase 203)

Water-tube firebox. Three-cylinder passenger locomotive, two with Baker gear (P-2), three with Walschaerts (P-3). Followed 2 years later by heavier, low-drivered freight version (2230) with lots of tractive effort, but much lower adhesive factor. According to Farrington (Railroading Coast to Coast, 1976), the DL&W's Scranton Shops removed the center cylinder in 1940. Drury, 1993, says this occurred much earlier, in 1930-1931 and the two cylinders were enlarged to 28" x 30".

Class P-4 (Locobase 202)

Firebox had thermic syphons. Low-drivered, 3-cylinder locomotive with a low adhesive factor. The 2 outside cylinders had 32-in strokes and drove the third axle while the inside cylinder had a 28-in stroke powering the second axle. This class followed a high-drivered (73") class in which all 3 cylinders had the same length stroke.

Because these freight locomotives put less demand for maintenance on that hard-to-get-at center cylinder, the Lackawanna left the arrangement intact throughout the class's lifetime. Retirement came in 1946-1950.

Specifications
Class	P-1	P-2/P-3	P-4
Locobase ID	5731	203	202
Railroad	Delaware, Lackawanna &Western	Delaware, Lackawanna &Western	Delaware, Lackawanna &Western
Whyte	4-8-2	4-8-2	4-8-2
Road Numbers	1401-1405	1451-1455	2201-2235
Gauge	Std	Std	Std
Builder	Alco-Brooks	Alco-Brooks	Alco
Year	1924	1925	1927
Valve Gear	Baker	Walschaert	Baker
	Locomotive Length and Weight
Driver Wheelbase	18.75'	19'	17.50'
Engine Wheelbase	41'	41.67'	39.92'
Ratio of driving wheelbase to overall engine wheebase	0.46	0.46	0.44
Overall Wheelbase (engine & tender)	77.17'	77.83'	75.79'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers	257500 lbs	256000 lbs	276500 lbs
Engine Weight	376000 lbs	382000 lbs	397500 lbs
Tender Light Weight	217300 lbs		215500 lbs
Total Engine and Tender Weight	593300 lbs	0	613000 lbs
Tender Water Capacity	12000 gals	12000 gals	12000 gals
Tender Fuel Capacity (oil/coal)	14 tons	14 tons	14 tons
Minimum weight per yard of rail on which locomotive could run	107.29 lb rail	106.67 lb rail	115 lb rail
	Geometry Relating to Tractive Effort
Driver Diameter	69"	73"	63"
Boiler Pressure	210 psi	200 psi	200 psi
Cylinders (dia x stroke)	28" x 30"	25" x 28" (3)	25" x 32"
Low Pressure Cylinders (dia x stroke)	" x "	" x "	25" x 28"
Tractive Effort	60845 lbs	61130 lbs	77579 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort)	4.23	4.19	3.56
	Heating Ability
Firebox Area	389 sq. ft	393 sq. ft	420 sq. ft
Grate Area	80.40 sq. ft	80 sq. ft	80 sq. ft
Evaporative Heating Surface	4978	4982	5010
Superheating Surface	1292	1290	1292
Combined Heating Surface	6270	6272	6302
Evaporative Heating Surface/Cylinder Volume	232.83	208.78	275.57
	Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation	16884	16000	16000
Same as above plus superheater percentage	20363.13	19290.82	19360
Same as above but substitute firebox area for grate area	98523.09	94766.14	101640
Power L1	20954.20	18923.61	49472
Power MT	717.61	651.87	1577.82