Statens Jarnvagar 4-4-2 Locomotives in Sweden


Class Details by Steve Llanso of Sweat House Media

Class A (Locobase 2781)

Data from "Express Locomotive - State Railroads of Sweden", Railroad Gazette, Volume 44, No. 9 (28 February 1908), pp. 280-282.

An interesting-looking combination of European and North American practice. As in other European designs, this Atlantic had a straight, uncluttered, boiler, flared stack, outside-frame leading truck, and inside motion. The high running board lent a North American scale to the drivers. An enclosed cab connoted due deference to the severe Scandanavian weather.

(NB: Heating surface areas in specifications use the exterior diameters of the tubes and flues. Using the interior diameters, evaporative heating surface area was 133 sq m/1,432 sq ft.)

Railroad Gazette discusses these engines at some length, noting the test runs which proved the value of the superheater. A Malmo-Nasijo (167 miles) series of trials resulted in 46.5% less coal consumption per ton-mile and 21.5% less water. According to RG, the maximum horsepower output came at 48 mph with 40% cutoff of the piston valves.

The Brimalm models website ([link]) explains that this class heralded the modern (and final) age of steam locomotive development in Sweden. But they soon were outmatched by express traffic demands (which were fulfilled by the famous F class compound Pacifics) and were relegated to light express and local passenger work and until the last was retired in 1939. Five of the 26 were sold to Ostkustbanan Railway and converted to 4-6-0s; these were designated A3. Three SJ engines were similarly treated in 1930 and designated A2 (Locobase 20207).

Principal Dimensions by Steve Llanso of Middle Run Media
ClassA
Locobase ID2781
RailroadStatens Jarnvagar (SJ)
CountrySweden
Whyte4-4-2
Number in Class26
Road Numbers1000-1025
GaugeStd
Number Built26
BuilderNydqvist & Holm (NOHAB)
Year1908
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m) 6.56 / 2
Engine Wheelbase (ft / m)28.54 / 8.70
Ratio of driving wheelbase to overall engine wheelbase 0.23
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)34,172 / 15,500
Weight on Drivers (lbs / kg)68,123 / 30,900
Engine Weight (lbs / kg)132,718 / 60,200
Tender Loaded Weight (lbs / kg)72,091 / 32,700
Total Engine and Tender Weight (lbs / kg)204,809 / 92,900
Tender Water Capacity (gals / ML)3696 / 14
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)5 / 5
Minimum weight of rail (calculated) (lb/yd / kg/m)57 / 28.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)74 / 1880
Boiler Pressure (psi / kPa)171.10 / 1180
High Pressure Cylinders (dia x stroke) (in / mm)19.69" x 23.62" / 500x600
Tractive Effort (lbs / kg)17,997 / 8163.31
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.79
Heating Ability
Tubes (number - dia) (in / mm)141 - 1.969" / 50
Flues (number - dia) (in / mm)18 - 5.236" / 133
Flue/Tube length (ft / m)15.09 / 4.60
Firebox Area (sq ft / m2)127.02 / 11.80
Grate Area (sq ft / m2)27.99 / 2.60
Evaporative Heating Surface (sq ft / m2)1596 / 148.25
Superheating Surface (sq ft / m2)353 / 32.80
Combined Heating Surface (sq ft / m2)1949 / 181.05
Evaporative Heating Surface/Cylinder Volume191.73
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4789
Same as above plus superheater percentage5651
Same as above but substitute firebox area for grate area25,645
Power L113,710
Power MT887.38

All material Copyright © SteamLocomotive.com
Wes Barris