Delaware & Hudson 4-6-6-4 "Challenger" Type Locomotives

Class J-95 (Locobase 338)

Data from tables in 1947 Locomotive Cyclopedia. Firebox heating surface included 5 thermic syphons of 77 sq ft total. Forty engines -- 1500-1519 purchased in 1940 (builder's numbers 69297-69316), 1520-1534 (70006-70020) over next 2 years, and 1535-1539 (74666-74670) procured in 1946.

Considered by many observers to be the handsomest of the Challenger type. More important, it was this class that introduced flat bearing surfaces on the front boiler supports. Alfred Bruce acknowledged in 1952 (p. 327): "The flat bearing-plate surfaces required careful alignment on the erecting floor, but they were well worth the effort."

Why? This modification in how the front engine was allowed to move under the boiler was combined with a new limitation on how much was allowed in the articulation pin's vertical clearance. Now the front engine moved only as much what its springs would allow, said Bruce, "..as in the case of the rigid-chassis engine."

The payoff in productivity was especially noticeable where the trackbed and alignment would allow it: "The result is the most stable-riding articulated engine ever built and one that is safely operated at speeds up to 60 or 70 miles per hour." At those speeds, Bruce declared, "[t]here are no smoother riding articulated steam locomotives today."

All were disposed off in 10 months from October 1952 to August 1953.

Specifications
ClassJ-95
Locobase ID338
RailroadDelaware & Hudson
Whyte4-6-6-4
Road Numbers1500-1539
GaugeStd
BuilderAlco-Schenectady
Year1940
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase12.17'
Engine Wheelbase59.92'
Ratio of driving wheelbase to overall engine wheebase 0.20
Overall Wheelbase (engine & tender)
Axle Loading (Maximum Weight per Axle)
Weight on Drivers406500 lbs
Engine Weight597000 lbs
Tender Light Weight311800 lbs
Total Engine and Tender Weight908800 lbs
Tender Water Capacity22500 gals
Tender Fuel Capacity (oil/coal)26 tons
Minimum weight per yard of rail on which locomotive could run113 lb rail
Geometry Relating to Tractive Effort
Driver Diameter69"
Boiler Pressure285 psi
Cylinders (dia x stroke)20.5" x 32" (4)
Tractive Effort94428 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.30
Heating Ability
Firebox Area633 sq. ft
Grate Area108.20 sq. ft
Evaporative Heating Surface5389
Superheating Surface1681
Combined Heating Surface7070
Evaporative Heating Surface/Cylinder Volume220.42
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation30837
Same as above plus superheater percentage38238
Same as above but substitute firebox area for grate area223702
Power L131748
Power MT1033.10

Photos

Reference

Credits

Introduction and specifications provided by Steve Llanso of Sweat House Media.