269 of the 400 or so standard Pacifics of the Etat received Chapelon-style rebuilds in the mid-1930s.
-- 134 231.D with Dabeg poppet valves fitted to the LP cylinders while retaining the Walschaert gear on the outside, HP cylinders.
The rebuilds worked their by-now familiar magic and these engines soldiered on for years running either fast express trains or pulling heavy 22-car troop trains.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | D 231 / 231 D |
| Locobase ID | 2587 |
| Railroad | Est |
| Country | France |
| Whyte | 4-6-2 |
| Number in Class | 134 |
| Road Numbers | |
| Gauge | Std |
| Number Built | |
| Builder | Etat |
| Year | 1933 |
| Valve Gear | various |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 13.75 / 4.19 |
| Engine Wheelbase (ft / m) | 36.81 / 11.22 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.37 |
| Overall Wheelbase (engine & tender) (ft / m) | 61.52 / 18.75 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 121,501 / 55,112 |
| Engine Weight (lbs / kg) | 212,323 / 96,308 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | 6632 / 25.12 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 7.70 / 7 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 68 / 34 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 76.80 / 1950 |
| Boiler Pressure (psi / kPa) | 224.80 / 1550 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 16.54" x 25.59" / 420x650 |
| Low Pressure Cylinders (dia x stroke) (in / mm) | 25.59" x 25.59" / 650x650 |
| Tractive Effort (lbs / kg) | 24,571 / 11145.23 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.94 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 128 - 2.165" / 55 |
| Flues (number - dia) (in / mm) | 26 - 5.63" / 143 |
| Flue/Tube length (ft / m) | 19.62 / 5.98 |
| Firebox Area (sq ft / m2) | 168.99 / 15.70 |
| Grate Area (sq ft / m2) | 45.75 / 4.25 |
| Evaporative Heating Surface (sq ft / m2) | 2226 / 206.80 |
| Superheating Surface (sq ft / m2) | 738 / 68.56 |
| Combined Heating Surface (sq ft / m2) | 2964 / 275.36 |
| Evaporative Heating Surface/Cylinder Volume | 349.79 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 10,285 |
| Same as above plus superheater percentage | 12,856 |
| Same as above but substitute firebox area for grate area | 47,486 |
| Power L1 | 18,347 |
| Power MT | 998.71 |