FS Class 685

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FS Class 685
FS locomotive 685.089 in 2010
Type and origin Power type Steam Builder Ernesto Breda (221) CEMSA (20), Officine Meccaniche, Milan (10) Officine Meccaniche e Navali (10) Reggiane (10) Build date 1912–1928 Total produced 271 + 120 rebuilds
Specifications Configuration: ​  • UIC 1′C1′ h4 Gauge 1,435 mm (4 ft 8+1⁄2 in) standard gauge Leading dia. 960 mm (3 ft 1+3⁄4 in) Driver dia. 1,850 mm (6 ft 7⁄8 in) Trailing dia. 1,220 mm (4 ft 0 in) Length 11,730 mm (38 ft 5+3⁄4 in) Axle load 15.1 tonnes (14.9 long tons; 16.6 short tons) Loco weight 70.8 tonnes (69.7 long tons; 78.0 short tons) Tender weight 48.6 tonnes (47.8 long tons; 53.6 short tons) Fuel type Coal Fuel capacity 6,000 kg (13,000 lb) Water cap. 22 m3 (4,840 imp gal; 5,810 US gal) Firebox: ​  • Grate area 3.5 m2 (38 sq ft) Boiler pressure 12 kg/cm2 (11.8 bar; 171 psi) Heating surface 191.8 m2 (2,065 sq ft) Superheater: ​  • Heating area 48.54 m2 (522.5 sq ft) Cylinders Four, simple Cylinder size 420 mm × 650 mm (16+9⁄16 in × 25+9⁄16 in) Valve gear Walschaerts (early production), Caprotti (late production)
Performance figures Maximum speed 120 km/h (75 mph) Power output 1,250 CV (919 kW; 1,230 hp) Tractive effort 11,300 kgf (111 kN; 24,900 lbf)
Career Operators Ferrovie dello Stato

The Ferrovie dello Stato (FS; Italian State Railways) Class 685 (Italian: Gruppo 685) is a class of 2-6-2 'Prairie' express train steam locomotives. These are colloquially known as Regine ('Queens' in Italian), mirroring their fame as one of the most successful and appreciated Italian steam locomotives.^[1]