Data from Albert H Bone, "Some Recent Designs of Locomotives for Service on Continental Railways", Cassier's Magazine, 1910, pp. 561-609; and "Locomotiva FNM 280" in Wikipedia at [], last accessed 11 April 2026. (Thanks to Ivo Rutishauser for his 7 April 2026 email noting the link that supplied on the class total, road and works identities and numbers.)
Henschel & Sohn works numbers were 9486-9488 and 10243-10245 in 1911. After World War I, class production resumed with Breda's 2052-2055, 2080 in 1923. Officine Meccaniche (OM) followed with 858-861 in 1926, and CEMSA completed the class with works numbers 801-804 in 1927. (Founded in 1925, CEMSA occupied the idle plant of the Costruzioni Meccaniche di Saronno.)
This burly looking Ten-wheeler tank had some unusual features. The water tanks was built up between the main frames and were not as apparent as most tank layouts. Their boilers had a mixture of 63 Serve tubes measuring 2.56" in diameter and 16 smoothbore tubes of 50 mm (1.97"). They also had Belpaire fireboxes.
The FNM 280s were the only ones on the railway rolling on a 4-6-0 arrangement. Bone describes the use of a bogie in front rather than a Bissel truck to "ensure steady running at high speeds." Offering power and 80 kph (50 mph) speed, the class served into the 1950s.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | unknown |
| Locobase ID | 8961 |
| Railroad | Ferrovie Nord Milano |
| Country | Italy |
| Whyte | 4-6-0T |
| Number in Class | 20 |
| Road Numbers | 281-296, 280.17-20/280.001-020 |
| Gauge | Std |
| Number Built | 20 |
| Builder | several |
| Year | 1908 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 13.12 / 4 |
| Engine Wheelbase (ft / m) | 27.23 / 8.30 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.48 |
| Overall Wheelbase (engine & tender) (ft / m) | 27.23 / 8.30 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 92,512 / 41,963 |
| Engine Weight (lbs / kg) | 145,600 / 66,043 |
| Tender Loaded Weight (lbs / kg) | |
| Total Engine and Tender Weight (lbs / kg) | |
| Tender Water Capacity (gals / ML) | 1663 / 6.30 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 2.20 / 1.50 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 51 / 25.50 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 63.80 / 1620 |
| Boiler Pressure (psi / kPa) | 171.90 / 1170 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 19.69" x 23.62" / 500x600 |
| Tractive Effort (lbs / kg) | 20,972 / 9512.75 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.41 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | |
| Flues (number - dia) (in / mm) | 21 - 5.236" / 133 |
| Flue/Tube length (ft / m) | 12.14 / 3.70 |
| Firebox Area (sq ft / m2) | 121.10 / 11.25 |
| Grate Area (sq ft / m2) | 25.83 / 2.40 |
| Evaporative Heating Surface (sq ft / m2) | 1367 / 127 |
| Superheating Surface (sq ft / m2) | 349 / 32.40 |
| Combined Heating Surface (sq ft / m2) | 1716 / 159.40 |
| Evaporative Heating Surface/Cylinder Volume | 164.22 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 4440 |
| Same as above plus superheater percentage | 5328 |
| Same as above but substitute firebox area for grate area | 24,981 |
| Power L1 | 11,228 |
| Power MT | 802.71 |