Ouest 4-6-2 Locomotives in France

Class Details by Steve Llanso of Sweat House Media

Class 2 901 (Locobase 2754)

Data from Robert Dubois,"Note on the Pacific Type of the French Western Railway," Bulletin of the International Railway Congress Association (English Edition), Volume XXII, No 12 (December 1908), pp. 1293-1299. See also Albert H Bone, "Some Recent Designs of Locomotives for Service on Continental Railways", Cassier's Magazine, 1910, pp. 561-609 and I N Jevica's [] (visited 29 May 2004) as well as info published on [] (visited November 2002) by Roland Arzul.

Rather massive-looking engines with their high-pitched Belpaire firebox, relatively tall drivers, and extended smokebox. All valve gear operation was outside, even though the HP cylinders were located between the frames, so a view of the locomotive shows two sets of Walschaert gear in tandem.

Arzul comments that the prototypes didn't lead directly to series production because the Ouest was absorbed by the Etat national system soon after they appeared. At the same time, their designer R. Dubois died prematurely. Even so, the Etat did base its first Pacifics on these two stylish locomotives; see Locobase 15170..

At first used in passenger service between Paris and Montparnasse, 2901 & 2902 (by then renumbered 231-001 and 231-002) were eventually relegated to mixed-traffic, then all-freight service. Retirement came quite early in 1928

Principal Dimensions by Steve Llanso of Sweat House Media

Class2 901
Locobase ID2754
Number in Class2
Road Numbers2 901-2 902 / 6 001-6 002
Number Built2
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.25 / 4.04
Engine Wheelbase (ft / m)34.68 / 10.57
Ratio of driving wheelbase to overall engine wheelbase 0.38
Overall Wheelbase (engine & tender) (ft / m)74.05 / 22.57
Axle Loading (Maximum Weight per Axle) (lbs / kg)39,352 / 17,850
Weight on Drivers (lbs / kg)118,057 / 53,550
Engine Weight (lbs / kg)199,959 / 90,700
Tender Loaded Weight (lbs / kg)125,663 / 57,000
Total Engine and Tender Weight (lbs / kg)325,622 / 147,700
Tender Water Capacity (gals / ML)6336 / 24
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 9.90 / 9
Minimum weight of rail (calculated) (lb/yd / kg/m)66 / 33
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)76.40 / 1941
Boiler Pressure (psi / kPa)227.70 / 15.70
High Pressure Cylinders (dia x stroke) (in / mm)15.75" x 25.2" / 400x640
Low Pressure Cylinders (dia x stroke) (in / mm)25.98" x 25.2" / 660x640
Tractive Effort (lbs / kg)23,160 / 10505.21
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.10
Heating Ability
Tubes (number - dia) (in / mm)283 - 2.165" / 55
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)19.69 / 6
Firebox Area (sq ft / m2)150.16 / 13.95
Grate Area (sq ft / m2)43.06 / 4
Evaporative Heating Surface (sq ft / m2)3047 / 283.05
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)3047 / 283.05
Evaporative Heating Surface/Cylinder Volume536.21
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9805
Same as above plus superheater percentage9805
Same as above but substitute firebox area for grate area34,191
Power L17122
Power MT398.99

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