Norfolk & Western 2-6-6-4 Type Locomotives

Class Details by Steve Llanso

Class A (Locobase 300)

One of Norfolk & Western's finest designs, these articulateds featured all the latest components when introduced in the late 1930s. After two appeared for trials (1200-1201), eight more followed in 1936-1937. N&W erected 25 more during World War II (using Alligator crosshead guides), and eight more in 1949-1950. Between Williamson, WV and Portsmouth, Ohio, these engines had a tonnage rating of 13,000 tons of slow freight. Between Portsmouth and Columbus, they were rated at 5,200 tons of time freight. And they could pull passenger trains at 70 mph.

In addition to a high-pressure boiler, an A had a cast-steel frame and roller bearings on virtually all surfaces. The firebox had 57 sq ft of arch tubes, but no circulators or syphons. The last five of the type had roller bearings in the side and main rods, the only articulateds to take such friction-reducing measures.

Max consumption rates per hour were 7 tons of coal burned and 116,055 lb of water evaporated.

Engine designs like these offer the best support for the contention that steam could equal diesel in cost-effective rail transport, but no other railroads could offer the combination of home-grown talent, facilities, and relatively cheap coal possessed by the N&W. Ultimately, even the N&W had to relent. All the As were retired in 1958-1959.

NB: Robert Le Massena (Trains, November 1991) says that this group had several traction-boosting differences that weren't publicized, such an increase in boiler pressure to 315 psi, drivers shrunk by half an inch to 69 1/2", and cylinders bored out to 24 1/2". The smokebox was insulated, valve gear pivoted on needle bearings, circulating tubes improved heating in the firebox. Total weight on the drivers increased 42,000 lb to 475,000 lb. Cutoff remained at 75%.

Locobase had not seen the May 1992 letter to Trains that contained an emphatic rebuttal of all of Le Massena's statements. Wikipedia also sources two articles from the N & W Historical Society that rejects the claims:

"# Newton, Louis M., "Setting the Record Straight on the Steam vs. Diesel Tests", The Arrow 10(3):14-17 (May 1994) (eyewitness denying secret improvements for the 1952 tests)

# Stephenson, David R., "Steam vs. Diesel: Did N&W Cheat?", The Arrow 14(1):14-18 (Jan. 1998) (technical analysis concluding that 1952 tests did not involve secret improvements or cheating)


Specifications by Steve Llanso
ClassA
Locobase ID300
RailroadNorfolk & Western (N&W)
CountryUSA
Whyte2-6-6-4
Road Numbers1200-1242
GaugeStd
BuilderN & W
Year1936
Valve GearBaker
Locomotive Length and Weight
Driver Wheelbase12.33'
Engine Wheelbase60.39'
Ratio of driving wheelbase to overall engine wheebase 0.20
Overall Wheelbase (engine & tender)108.27'
Axle Loading (Maximum Weight per Axle)72000 lbs
Weight on Drivers433350 lbs
Engine Weight573000 lbs
Tender Light Weight378600 lbs
Total Engine and Tender Weight951600 lbs
Tender Water Capacity22000 gals
Tender Fuel Capacity (oil/coal)26 tons
Minimum weight of rail (calculated) on which locomotive could run120 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter70"
Boiler Pressure300 psi
Cylinders (dia x stroke)24" x 30" (4)
Tractive Effort125897 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.44
Heating Ability
Firebox Area587 sq. ft
Grate Area122 sq. ft
Evaporative Heating Surface6639 sq. ft
Superheating Surface2703 sq. ft
Combined Heating Surface9342 sq. ft
Evaporative Heating Surface/Cylinder Volume211.33
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation36600
Same as above plus superheater percentage47214
Same as above but substitute firebox area for grate area227169
Power L137769
Power MT1152.87

Photos

Reference

Credits

Introduction and roster provided by Richard Duley. Class details and specifications provided by Steve Llanso of Sweat House Media.