Midi 2-2-2 Locomotives in France

Class Details by Steve Llanso of Sweat House Media

Class 1 (Locobase 6850)

Data from August Perdonnet et Camille Polonceau, Nouveau Portefeuille de L'Ingenieur des Chemins de Fer, Tome Second (Paris: Librairie Scientifique, Industrielle et Agricole, 1866), pp. 528-529. See also Titre Rapports du jury mixte internationale publies sous la dir. de S.A.I le Prince Napoleon, presidente de la commission Imperial (Paris, Impremerie Imperiale, 1856) Collation [4]-LXXVI-1574-p. -[2]; Cote CNAM 8th Xae 53 - Mots mateiere Exposition internationale (1885; Paris); Industrie - 19e siecle; Produits industriels - 19e siecle, p. 233, hosted on cnum.cnam.fr/CGI/fpage.cgi?8XAE53/320/100/1664/0/0, accessed 1 September 2005.

According to the jury report for the 1855 Exposition, these locomotives had the same boiler and cylinders as the mixed-traffic tanks shown in 6849. But the running gear featured much taller "roues independants", which Locobase believes refers to the single-driver arrangement shown in the Whyte field. It must indeed have been fast, but its tractive effort limited train load.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID6850
Number in Class40
Road Numbers1-100
Number Built40
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)
Engine Wheelbase (ft / m)15.19 / 4.63
Ratio of driving wheelbase to overall engine wheelbase
Overall Wheelbase (engine & tender) (ft / m)32.37 / 9.87
Axle Loading (Maximum Weight per Axle) (lbs / kg)28,881 / 13,100
Weight on Drivers (lbs / kg)28,660 / 13,000
Engine Weight (lbs / kg)62,170 / 28,200
Tender Loaded Weight (lbs / kg)42,329 / 19,200
Total Engine and Tender Weight (lbs / kg)104,499 / 47,400
Tender Water Capacity (gals / ML)660 / 2.50
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 1.50 / 1
Minimum weight of rail (calculated) (lb/yd / kg/m)48 / 24
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)82.30 / 2090
Boiler Pressure (psi / kPa)113.10 / 7.80
High Pressure Cylinders (dia x stroke) (in / mm)16.54" x 22.05" / 420x560
Tractive Effort (lbs / kg)7046 / 3196.02
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.07
Heating Ability
Tubes (number - dia) (in / mm)180 - 1.969" / 50
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)11.35 / 3.46
Firebox Area (sq ft / m2)81.05 / 7.53
Grate Area (sq ft / m2)14.53 / 1.35
Evaporative Heating Surface (sq ft / m2)1050 / 97.53
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1050 / 97.53
Evaporative Heating Surface/Cylinder Volume191.48
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation1643
Same as above plus superheater percentage1643
Same as above but substitute firebox area for grate area9167
Power L14117
Power MT316.69

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