Data from the US Military Railway Service's Equipment Data Book for Italian Locomotives supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange; and "Recent Italian State Railway Steam Locomotives', Locomotive Magazine, Volume XXIX [29] (15 September 1923), pp. 258-259.
These decapods seem to have been based on the FS 746 class of Mikados shown in Locobase 3506. They had the same grate area, although the overall area was smaller. The boiler tubes were much shorter. The trailing axle was traded for another set of drivers, which increased adhesion by 11 1/2 short tons. Lower drivers meant only a slight increase in driving wheelbase and the axle loading dropped.
Gruppo 480 boilers were rated at 26,620 lb (12,075 kg) per hour; horsepower rating was 1,500 at 24 mph. Although the steaming rate is almost identical to that of the 746s, peak horsepower came at a much lower speed.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | Gruppo 480 |
| Locobase ID | 6618 |
| Railroad | Ferrovie dello Stato (FS) |
| Country | Italy |
| Whyte | 2-10-0 |
| Number in Class | 18 |
| Road Numbers | 480 001 - 480 018 |
| Gauge | Std |
| Number Built | 18 |
| Builder | Breda |
| Year | 1922 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 20.33 / 6.20 |
| Engine Wheelbase (ft / m) | 39.90 / 8.80 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.51 |
| Overall Wheelbase (engine & tender) (ft / m) | 59.98 / 18.28 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | 33,000 / 14,969 |
| Weight on Drivers (lbs / kg) | 165,000 / 74,843 |
| Engine Weight (lbs / kg) | 185,460 / 84,123 |
| Tender Loaded Weight (lbs / kg) | 110,220 / 49,995 |
| Total Engine and Tender Weight (lbs / kg) | 295,680 / 134,118 |
| Tender Water Capacity (gals / ML) | 6050 / 22.92 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 6.60 / 6 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 55 / 27.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 53.90 / 1369 |
| Boiler Pressure (psi / kPa) | 170 / 1170 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 26.38" x 25.59" / 670x650 |
| Tractive Effort (lbs / kg) | 47,742 / 21655.43 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.46 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 195 - 2.063" / 52 |
| Flues (number - dia) (in / mm) | 27 - 5.23" / 133 |
| Flue/Tube length (ft / m) | 16.90 / 5.15 |
| Firebox Area (sq ft / m2) | 156 / 14.50 |
| Grate Area (sq ft / m2) | 46.27 / 4.30 |
| Evaporative Heating Surface (sq ft / m2) | 2338 / 217.30 |
| Superheating Surface (sq ft / m2) | 647 / 60 |
| Combined Heating Surface (sq ft / m2) | 2985 / 277.30 |
| Evaporative Heating Surface/Cylinder Volume | 144.43 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 7866 |
| Same as above plus superheater percentage | 9596 |
| Same as above but substitute firebox area for grate area | 32,354 |
| Power L1 | 8435 |
| Power MT | 563.51 |