FS Class 680 | |||||||||||||||||||||||||||||||||||||||||||
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FS locomotive 680.037 as preserved
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Type and origin | |
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Power type | Steam |
Builder |
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Build date | 1907–1911 |
Total produced | 151 |
Specifications | |
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Configuration: |
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• UIC | 1′C1′ n4v |
Gauge | 1,435 mm (4 ft 8 1⁄2 in) |
Leading dia. | 960 mm (37.80 in) |
Driver dia. | 1,850 mm (72.83 in) |
Trailing dia. | 1,220 mm (48.03 in) |
Length | 11,980 mm (39 ft 3 5⁄8 in) |
Axle load | 15 tonnes (15 long tons; 17 short tons) |
Loco weight | 70 tonnes (69 long tons; 77 short tons) |
Tender weight | 40.5 tonnes (39.9 long tons; 44.6 short tons) |
Fuel type | Coal |
Fuel capacity | 6,000 kg (13,000 lb) |
Water cap | 20,000 l (4,400 imp gal; 5,300 US gal) |
Firebox: • Firegrate area |
3.5 m2 (38 sq ft) |
Boiler pressure | 16 kg/cm2 (1.57 MPa; 228 psi) |
Heating surface | 219.26 m2 (2,360.1 sq ft) |
Cylinders | Four, compound |
High-pressure cylinder | 360 mm × 650 mm (14.17 in × 25.59 in) |
Low-pressure cylinder | 590 mm × 650 mm (23.23 in × 25.59 in) |
Valve gear | Walschaerts |
Performance figures | |
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Maximum speed | 110 km/h (68 mph) |
Power output | 1,150 CV (846 kW; 1,130 hp) |
Tractive effort | 9,000 kgf (88.3 kN; 19,800 lbf) |
The Ferrovie dello Stato Italiane (FS; Italian State Railways) Class 680 (Italian: Gruppo 680) is a 2-6-2 express steam locomotive; it was the direct ancestor of the very successful and appreciated Class 685.
The Class 680 was designed as the "normalized" successor of the famous Class 500 (reclassified by the Ferrovie dello Stato as Class 670) fast locomotives of the Rete Adriatica; in fact, even before the RA ended up being nationalized in the Ferrovie dello Stato in 1905, there was already a project (with the projected classification RA 550 for a fast 2-6-2 locomotive which shared several similarities with what would end up becoming, under the FS ownership, the Class 680.
The Class featured the widespread Italian bogie, and the same Plancher compound engine of the Class 500, an arrangement in which the two high pressure (HP) and the two low pressure (LP) cylinders were paired together respectively on the left and the right side of the locomotive, with each pair being served by a single piston valve via crossed ports. This ingenious arrangement was simple, but it made the locomotive somewhat unbalanced and unstable, especially at higher speed.
The Class 680 was built from 1907 to 1909 in 151 units by Ernesto Breda, Gio. Ansaldo & C. and Berliner Maschinenbau, with the last two locomotives being built by the former company respectively in 1909 and 1911.
Initially, the Class 680 was fitted with a three-axle tender with a water capacity of 20,000 litres (4,400 imp gal; 5,300 US gal), but it proved prone to derail at high speeds (especially on the Genoa-Ventimiglia line); therefore, those were swapped with the bogie tenders of the Class 625, with a higher capacity of 22,000 litres (4,800 imp gal; 5,800 US gal).
The first locomotive, when outshopped from the Ernesto Breda factory in 1907, was initially assigned the classification FS 6401, but a few days later it was reclassified FS 6801. Over the next years, new classifications with five and eventually six numbers (with the class and the running numbers separated by a full stop) were adopted, the class ending up as 680.XXX.