Duluth, South Shore, & Atlantic 4-6-2 "Pacific" Locomotives in 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 Rail Data Exchange. Works numbers were 51417-51418 in July 1912.

Small, light passenger locomotives originally delivered with 64" (1,626 mm) 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 Rail Data Exchange.

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.

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Class H-2 (Locobase 6667)

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

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
BuilderAlco-SchenectadyAlco-BrooksAlco-Brooks
Year191219131924
Valve GearWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12 / 3.6612 / 3.6612 / 3.66
Engine Wheelbase (ft / m)32.42 / 9.8832.42 / 9.8832.42 / 9.88
Ratio of driving wheelbase to overall engine wheebase 0.37 0.37 0.37
Overall Wheelbase (engine & tender) (ft / m)57.92 / 17.6555.17 / 16.8258.48 / 17.82
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)115,000 / 52,163124,450 / 56,450129,000 / 58,513
Engine Weight (lbs / kg)185,000 / 83,915196,850 / 89,290203,000 / 92,079
Tender Loaded Weight (lbs / kg)113,033 / 51,271113,033 / 51,271123,000 / 55,792
Total Engine and Tender Weight (lbs / kg)298,033 / 135,186309,883 / 140,561326,000 / 147,871
Tender Water Capacity (gals / ML)5800 / 21.976000 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)9 / 8.2010 / 9.10
Minimum weight of rail (calculated) (lb/yd)646972
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)67 / 170267 / 170267 / 1702
Boiler Pressure (psi / kPa)180 / 12.40180 / 12.40200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)20.5" x 26" / 521x66021" x 26" / 533x66021" x 26" / 533x660
Tractive Effort (lbs / kg)24,952 / 11318.0526,184 / 11876.8829,093 / 13196.38
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.61 4.75 4.43
Heating Ability
Firebox Area (sq ft / m2)188 / 17.47188 / 17.47190 / 17.66
Grate Area (sq ft / m2)46.30 / 4.3046.30 / 4.3046.30 / 4.30
Evaporative Heating Surface (sq ft / m2)1643 / 152.701643 / 152.701540 / 143.12
Superheating Surface (sq ft / m2)363 / 33.74363 / 33.74415 / 38.57
Combined Heating Surface (sq ft / m2)2006 / 186.442006 / 186.441955 / 181.69
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 percentage9834983411,205
Same as above but substitute firebox area for grate area39,93139,93145,980
Power L111,83811,28113,338
Power MT680.82599.53683.84