Delaware, Lackawanna & Western / Delaware, Lackawanna &Western 4-8-2 "Mountain" Locomotives of the USA

The Delaware Lackawanna & Western Railroad took delivery of five 4-8-2s (road numbers 1401 through 1405) from the American Locomotive Company in 1924. These "Mountains" had 69" drivers and were not particularly well suited for passenger service and were relegated to secondary trains. They were sold to the Atlantic Coast Line Railroad during World War II.

Five more 4-8-2s (road numbers 1450 through 1454) came from ALCO in 1925. These locomotives had three 25" x 28" cylinders, 73" drivers, a 200 psi boiler pressure and exerted 61,100 lbs of tractive effort. By 1931 DL&W had rebuilt them as two cylinder locomotives.

In 1926 and 1927, the DL&W received thirty more "Mountains" (road numbers 2201 through 2235) from ALCO to be used as pushers and to drag coal trains. These locomotives had three cylinders, two 25 x 32 outside cylinders driving the third drivers and one 25 x 28 inside cylinder driving a crank on the second axle. With 73" drivers and a boiler pressure of 200 psi they exerted 77,600 lbs of tractive effort.

By 1950, all of the DL&W "Mountains" were gone and there are no surviving examples.

Roster by Richard Duley

Qty.Road NumbersYear BuiltBuilderRemarks
51401-14051924ALCO2 cylinders
51450-14541925ALCO3 cylinders rebuilt as 2 cylinders
302201-22351926-1927ALCO3 cylinders
Note: Numbers 1450-1454 were rebuilt as two cylinder locomotives

Class Details by Steve Llanso of Sweat House Media

Class P-1 (Locobase 5731)

Data from set of DL&W locomotive diagrams at (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). Works numbers were 65418-65422 in March 1924. Works numbers were 65418-65422 in March 1924.

Firebox heating surface included 35 sq ft (3.25 sq m) of arch tubes. Each cylinder was fed through relatively small 11" (279 mm) piston valve.

Drury (1993) says these five 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)

Data from tables in 1930 Locomotive Cyclopedia. See also DL&W 7 - 1933 Locomotive Diagrams supplied in May 2005 by Allen Stanley. (Thanks to Chris Hohl for his 11 November 2012 email noting a discrepancy in road numbers.) Works numbers were 66163-66164 in April 1925 and 66428-66430 in September.

Water-tube firebox. Three-cylinder passenger locomotive, two with Baker gear (P-2), three with Walschaert (P-3). Followed two years later by heavier, low-drivered freight version (Locobase 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 32" (711 x 813 mm). The locomotive diagrams confirm Drury and show also that, as modified, 1450 and 1452 had 11" (279 mm) piston valves and 1451, 1453-1454 had 14" (356 mm) piston valves. All of the engines used Walschaert gear at that point, but the P-2's (1450-1451) valve travel measured 7 1/2" (191 mm) while the P-3a valves traveled 9" (229 mm).

Class P-4/P-5 (Locobase 202)

Data from tables in 1930 Locomotive Cyclopedia and DL&W 7 - 1933 Locomotive Diagrams supplied by Allen Stanley in May 2005 Works numbers were 66954-66964 in September; 66965-67524 in October, and 67525 in November.

Firebox heating surface are included 80 sq ft (7.43 sq m) in Superior E-type thermic syphons and 24 sq ft (2.23 sq m) . Low-drivered, three-cylinder locomotive with a low adhesive factor. The two 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 three cylinders had the same length stroke. The three cylinders each had a 12" (305 mm) piston valve.

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 by Steve Llanso of Sweat House Media
Locobase ID5731 203 202
RailroadDelaware, Lackawanna &WesternDelaware, Lackawanna &WesternDelaware, Lackawanna & Western
Number in Class5535
Road Numbers1401-14051450-14542201-2225, 2226-2235
Number Built5535
Valve GearWalschaertBaker or WalschaertBaker
Locomotive Length and Weight
Driver Wheelbase (ft)18.751917.50
Engine Wheelbase (ft)4141.6739.92
Ratio of driving wheelbase to overall engine wheebase 0.46 0.46 0.44
Overall Wheelbase (engine & tender) (ft)77.1777.8375.79
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)257,500256,000276,500
Engine Weight (lbs)376,000382,000397,500
Tender Loaded Weight (lbs)217,300218,600215,500
Total Engine and Tender Weight (lbs)593,300600,600613,000
Tender Water Capacity (gals)12,00012,00012,000
Tender Fuel Capacity (oil/coal) (gals/tons)141614
Minimum weight of rail (calculated) (lb/yd)107107115
Geometry Relating to Tractive Effort
Driver Diameter (in)697363
Boiler Pressure (psi)210200200
High Pressure Cylinders (dia x stroke) (in)28" x 30"25" x 28" (3)25" x 32"
Low Pressure Cylinders (dia x stroke) (in)25" x 28" (1)
Tractive Effort (lbs)60,84561,13077,579
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.23 4.19 3.56
Heating Ability
Firebox Area (sq ft)389393420
Grate Area (sq ft)80.408080
Evaporative Heating Surface (sq ft)497849825010
Superheating Surface (sq ft)129212901292
Combined Heating Surface (sq ft)627062726302
Evaporative Heating Surface/Cylinder Volume232.83208.78275.57
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation16,88416,00016,000
Same as above plus superheater percentage20,43019,36019,360
Same as above but substitute firebox area for grate area98,84595,106101,640
Power L120,95418,92415,057
Power MT717.60651.88480.22



If you have any railroad data such as diagram books, rail station plans or anything else that you would be willing to share, please contact us.