4-4-6 Steam Locomotives in France

Thuile Locomotive


Class Details by Steve Llanso of Sweat House Media

Class unknown (Locobase 2502)

Data from F Barbier and R Godfernaux,"Locomotive a Grand Vitesse, Systeme Thuile", Les Locomotives de l'Exposition de 1900" (Paris: V Ch. Dunod, 1902), pp.204-210; and Gustav Reder (Michael Reynolds, trans), The World of Steam Locomotives (New York: Putnam, 1974). (Thanks to Alexander Blessing for his 16 June 2024 email supplying corrected data and the link to Barbier & Godfernaux book that supplied it.)

Designed to a requirement for a locomotive that could pull a luxury passenger train of 180-200 tons at 120 kph (76 mph), this cab-forward engine, rated at1,600-1,800 cylinder horsepower, debuted at the International Exhibition in Paris in 1900.

The engine showed several features intended to achieve high-speed performance. A short boiler pear-shaped in cross-section rode behind the engineer's wedge-shaped cab. Its large-diameter Serve tubes had the internal fluting characteristic of the type. While the engineer watched ahead, two firemen stoked the large Belpaire firebox, which extended over a three-axle pivoting bogie.

A five-axle tender, itself an unusual arrangement, carried enough water to confer a 180 km (112 miles) range on the locomotive. Coal capacity eqaated to a 350 km (217 miles) range, about twice as far as the water tank.

Test runs showed the Thuile pulling a 205 ton train up a 1% grade at 80 kph (50 mph). According to Reder, however, the engine was not a success, barely making its intended speed and derailing often. When the designer was killed during one test (by putting his head in the way of a lineside pole), further development was abandoned.

(See also The Locomotive Magazine, October 1900)

Principal Dimensions by Steve Llanso of Middle Run Media
Classunknown
Locobase ID2502
RailroadThuile Locomotive
CountryFrance
Whyte4-4-6
Number in Class1
Road Numbers
GaugeStd
Number Built1
BuilderSchneider-Creusot
Year1900
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m) 9.19 / 2.80
Engine Wheelbase (ft / m)40.19 / 12.25
Ratio of driving wheelbase to overall engine wheelbase 0.23
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)35,274 / 16,000
Weight on Drivers (lbs / kg)70,548 / 32,000
Engine Weight (lbs / kg)177,210 / 80,381
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)7265 / 27.52
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 7.70 / 7
Minimum weight of rail (calculated) (lb/yd / kg/m)59 / 29.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)98.40 / 2500
Boiler Pressure (psi / kPa)213.20 / 1470
High Pressure Cylinders (dia x stroke) (in / mm)20.08" x 27.56" / 510x700
Tractive Effort (lbs / kg)20,465 / 9282.78
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.45
Heating Ability
Tubes (number - dia) (in / mm)183 - 2.244" / 57
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)14.27 / 4.35
Firebox Area (sq ft / m2)263.72 / 24.50
Grate Area (sq ft / m2)50.38 / 4.68
Evaporative Heating Surface (sq ft / m2)3204 / 297.70
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)3204 / 297.70
Evaporative Heating Surface/Cylinder Volume317.18
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,741
Same as above plus superheater percentage10,741
Same as above but substitute firebox area for grate area56,225
Power L115,654
Power MT978.37

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