Data from users.libero.it/allesandro.tuzza/fonti/sfr/1879sfrindice.htm (8 July 2004), an 1878 album of locomotives for the SFR reproduced by Allesandro Tuzza. (later cite: [], Tavola 13.)
A year after SFR 121 was produced, Stephenson delivered two more (works 721-722) with the same cylinder and driver dimensions. The profile had changed, however, the dome now had a more rounded contour with a flat top, the sand box cylinder was just ahead and the firebox had only a slender (yet still tall) column for the safety valve. Power increased with higher boiler pressure.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | 131 |
| Locobase ID | 6243 |
| Railroad | Strade Ferrate Centrale Toscana (SFCT) |
| Country | Italy |
| Whyte | 2-4-0 |
| Number in Class | 2 |
| Road Numbers | 131-132 |
| Gauge | Std |
| Number Built | 2 |
| Builder | Robert Stephenson & Co |
| Year | 1849 |
| Valve Gear | Stephenson |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 5.22 / 1.59 |
| Engine Wheelbase (ft / m) | 10.76 / 3.28 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.49 |
| Overall Wheelbase (engine & tender) (ft / m) | 29.05 / 8.86 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 19,180 / 8700 |
| Weight on Drivers (lbs / kg) | 37,919 / 17,200 |
| Engine Weight (lbs / kg) | 54,675 / 24,800 |
| Tender Loaded Weight (lbs / kg) | 37,479 / 17,000 |
| Total Engine and Tender Weight (lbs / kg) | 92,154 / 41,800 |
| Tender Water Capacity (gals / ML) | 1320 / 5 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 32 / 16 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 60 / 1517 |
| Boiler Pressure (psi / kPa) | 101.50 / 700 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 15" x 24" / 381x610 |
| Tractive Effort (lbs / kg) | 7765 / 3522.15 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.88 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 133 - 1.929" / 49 |
| Flues (number - dia) (in / mm) | |
| Flue/Tube length (ft / m) | 13.52 / 4.12 |
| Firebox Area (sq ft / m2) | 61.33 / 5.70 |
| Grate Area (sq ft / m2) | 10.76 / 1 |
| Evaporative Heating Surface (sq ft / m2) | 912 / 84.78 |
| Superheating Surface (sq ft / m2) | |
| Combined Heating Surface (sq ft / m2) | 912 / 84.78 |
| Evaporative Heating Surface/Cylinder Volume | 185.79 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 1092 |
| Same as above plus superheater percentage | 1092 |
| Same as above but substitute firebox area for grate area | 6225 |
| Power L1 | 2520 |
| Power MT | 293.03 |