SNCB 4-6-2 Locomotives in Belgium

Class Details by Steve Llanso of Sweat House Media

Class 1 (Locobase 2601)

Data from "La Construction des LOCOMOTIVES a VAPEUR en Belgique" (15 August 1938), monthly journal of La Federation des Constructeurs, hosted on [] (last accessed 29 Sept 2007).

These large, semi-streamlined Pacifics were the largest and heaviest of that wheel arrangement built outside of North America. They had such large fireboxes that firemen used side-by-side firedoors. ACFI (Compagnie des Auxiliaires des Chemins de Fer et de l'Industrie) feedwater heaters, four 250-mm (9.84") diameter piston valves, and double Kylchap stack assemblies further improved this engine's efficiency. The valves and cylinders were cast in a single block.

At approximately 90 km/h (55 mph), dynamometer measurements showed the Type 1 putting out more than 2,500 hp. It could pull a 505-ton train up a 0.4% grade at 100 km/h (62 mph) and up a 1.6% grade at 70 km/h (43.5 mph).

NB: Belgian tube heating surface calculation reflected the interior diameters of the tubes and flues. Together with the firebox area, the result came to 234.78 sq m (2,526 sq ft). Calculating the tube heating surface from the outside diameters given in the data fiche yields the figure shown above.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID2601
Number in Class35
Road Numbers101-135
Number Built35
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.45 / 4.10
Engine Wheelbase (ft / m)37.57 / 11.45
Ratio of driving wheelbase to overall engine wheelbase 0.36
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)52,920 / 24,004
Weight on Drivers (lbs / kg)158,733 / 72,000
Engine Weight (lbs / kg)277,782 / 126,000
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)10,499 / 39.77
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)88 / 44
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)78 / 1980
Boiler Pressure (psi / kPa)255.30 / 17.60
High Pressure Cylinders (dia x stroke) (in / mm)16.54" x 28.35" / 420x720 (4)
Tractive Effort (lbs / kg)43,155 / 19574.80
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.68
Heating Ability
Tubes (number - dia) (in / mm)131 - 2.165" / 55
Flues (number - dia) (in / mm)38 - 5.394" / 137
Flue/Tube length (ft / m)19.69 / 6
Firebox Area (sq ft / m2)212.27 / 19.72
Grate Area (sq ft / m2)53.82 / 5
Evaporative Heating Surface (sq ft / m2)2731 / 253.70
Superheating Surface (sq ft / m2)1202 / 111.70
Combined Heating Surface (sq ft / m2)3933 / 365.40
Evaporative Heating Surface/Cylinder Volume193.68
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation13,740
Same as above plus superheater percentage18,000
Same as above but substitute firebox area for grate area70,992
Power L134,389
Power MT1432.87

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