Seaboard Air Line 2-6-6-4 Locomotives of the USA


Class Details by Steve Llanso of Sweat House Media

Class R-1 (Locobase 302)

Data from tables and diagrams in 1947 Locomotive Cyclopedia and from from the 1948 SAL locomotive diagram supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers ran 61829-61833.

See Trains Magazine (August 1979) for an account of how these engines ran. They were well-liked with many engineers feeling that they were capable of higher speeds than the road would let them reach.

See Locobase 10077 for the later batch of R-2s, which had slightly different specs.


Class R-2 (Locobase 10077)

Data from tables and diagrams in 1947 Locomotive Cyclopedia and from from the 1948 SAL locomotive diagram supplied in May 2005 by Allen Stanley from his extensive Raildata collection..

These R-2s (works numbers 62054-62058) had slightly fewer tubes than the earlier R-1, a cleaner-looking Walschaerts valve motion, single crosshead guides, and Elesco feedwater heaters replaced by Worthingtons, but otherwise varied little from the earlier R-1s.

These engines later (1947) went on to the B&O as KB-1 and KB-1a 7700-7709, where the slip joints in the piping to the front engine unit (which leaked frequently) were replaced by ball joints. They were slippery on grades and not as well liked as the Big Sixes (2-10-2), although a later relocation of the air pumps to the pilot on one engine reduced the slipping.

Specifications by Steve Llanso of Sweat House Media
ClassR-1R-2
Locobase ID302 10077
RailroadSeaboard Air Line (SAL)Seaboard Air Line (SAL)
CountryUSAUSA
Whyte2-6-6-42-6-6-4
Number in Class55
Road Numbers2500-25042505-2509
GaugeStdStd
Number Built55
BuilderBaldwinBaldwin
Year19351937
Valve GearBakerWalschaert
Locomotive Length and Weight
Driver Wheelbase12'12'
Engine Wheelbase67.42'67.42'
Ratio of driving wheelbase to overall engine wheebase 0.18 0.18
Overall Wheelbase (engine & tender)97.75'97.75'
Axle Loading (Maximum Weight per Axle)55000 lbs55000 lbs
Weight on Drivers330000 lbs330000 lbs
Engine Weight480000 lbs480000 lbs
Tender Light Weight310200 lbs310200 lbs
Total Engine and Tender Weight790200 lbs790200 lbs
Tender Water Capacity16000 gals16000 gals
Tender Fuel Capacity (oil/coal)24 tons24 tons
Minimum weight of rail (calculated)92 lb/yard92 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter69"69"
Boiler Pressure230 psi230 psi
Cylinders (dia x stroke)22" x 30"22" x 30"
Tractive Effort82280 lbs82280 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.01 4.01
Heating Ability
Firebox Area516 sq. ft515 sq. ft
Grate Area96.30 sq. ft96.30 sq. ft
Evaporative Heating Surface5513 sq. ft5429 sq. ft
Superheating Surface2397 sq. ft2397 sq. ft
Combined Heating Surface7910 sq. ft7826 sq. ft
Evaporative Heating Surface/Cylinder Volume208.84205.66
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation2214922149
Same as above plus superheater percentage2879429015
Same as above but substitute firebox area for grate area154284155170
Power L12972429635
Power MT1191.461187.89

Reference


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