Duluth, South Shore, & Atlantic 4-6-2 "Pacific" Locomotives of the USA


Class Details by Steve Llanso of Sweat House Media

Class H (Locobase 1330)

Data from DSS&A 1-1944 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

Small, light passenger locomotives originally delivered with 64" drivers and developing 26,121 lb TE. Firebox heating surface included 28 sq ft of arch tubes. Later fitted with 67" drivers. 550 dismantled in June 1942, 551 in August 1944. (One supposes demand for passenger service along the southern shore of Lake Superior must not have very high in wartime to allow these two relatively young locomotives to be scrapped.)

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Class H-1 (Locobase 1331)

Data from DSS&A 1-1944 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

The largest passenger locomotives delivered to the Duluth, South Shore, and Atlantic. Served until 1951. Two more Pacifics (555-556) were delivered after 1922. One irony about wheel arrangements: this railroad, which so optimistically carried the Atlantic as its ultimate destination, never had a 4-4-2 in its stud.

(http:/fp-www.wwnet.net/`dulong/dssa/locomot.thm)


Class H-2 (Locobase 6667)

Data from DSS&A 1-1944 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

This pair followed the first two batches (Locobase 1330, 1331) from Brooks by 9 years. Although the new locomotives maintained much of the original light Pacific design, they traded heating tubes for a substantial amount of superheat. Firebox heating surface included 28 sq ft (2.6 sq m) of arch tubes. The radial valve gear worked 12" (305 mm) piston valves.

Specifications by Steve Llanso of Sweat House Media
ClassHH-1H-2
Locobase ID1330 1331 6667
RailroadDuluth, South Shore, & AtlanticDuluth, South Shore, & AtlanticDuluth, South Shore, & Atlantic
CountryUSAUSAUSA
Whyte4-6-24-6-24-6-2
Number in Class232
Road Numbers550-551552-554555-556
GaugeStdStdStd
Number Built232
BuilderAlcoAlco-BrooksAlco-Brooks
Year191219131924
Valve GearWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase12'12'12'
Engine Wheelbase32.42'32.42'32.42'
Ratio of driving wheelbase to overall engine wheebase 0.37 0.37 0.37
Overall Wheelbase (engine & tender)57.92'55.17'58.48'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers115000 lbs124450 lbs129000 lbs
Engine Weight185000 lbs196850 lbs203000 lbs
Tender Light Weight113033 lbs113033 lbs123000 lbs
Total Engine and Tender Weight298033 lbs309883 lbs326000 lbs
Tender Water Capacity5800 gals6000 gals
Tender Fuel Capacity (oil/coal)9 tons10 tons
Minimum weight of rail (calculated)64 lb/yard69 lb/yard72 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter67"67"67"
Boiler Pressure180 psi180 psi200 psi
Cylinders (dia x stroke)20.5" x 26"21" x 26"21" x 26"
Tractive Effort24952 lbs26184 lbs29093 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.61 4.75 4.43
Heating Ability
Firebox Area188 sq. ft188 sq. ft190 sq. ft
Grate Area46.30 sq. ft46.30 sq. ft46.30 sq. ft
Evaporative Heating Surface1643 sq. ft1643 sq. ft1540 sq. ft
Superheating Surface363 sq. ft363 sq. ft415 sq. ft
Combined Heating Surface2006 sq. ft2006 sq. ft1955 sq. ft
Evaporative Heating Surface/Cylinder Volume165.42157.63147.75
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation833483349260
Same as above plus superheater percentage9834983411205
Same as above but substitute firebox area for grate area399313993145980
Power L1118381128113338
Power MT680.82599.53683.84


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