FS Class 691

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FS Class 691
20110726 FS 691 Milan Museo 6290.jpg
FS locomotive 691.022 as preserved at the Museo nazionale della Scienza e della Tecnologia "Leonardo da Vinci", Milan
Type and origin
Power typeSteam
Rebuilder
Rebuild date1928–1934
Number rebuilt33 rebuilt (from Class 690)
Specifications
Configuration:
   UIC 2′C1′ h4
Gauge 1,435 mm (4 ft 8+12 in) standard gauge
Leading dia. 1,090 mm (3 ft 6+78 in)
Driver dia.2,030 mm (6 ft 7+78 in)
Trailing dia. 1,230 mm (4 ft 38 in)
Length13,880 mm (45 ft 6+12 in)
Axle load 20 tonnes (20 long tons; 22 short tons)
Loco weight96 tonnes (94 long tons; 106 short tons)
Tender weight56 tonnes (55 long tons; 62 short tons)
Total weight152 tonnes (150 long tons; 168 short tons)
Fuel type Coal
Fuel capacity5,500 kg (12,100 lb)
Water cap.29 m3 (6,380 imp gal; 7,660 US gal)
Firebox:
  Grate area4.3 m2 (46 sq ft)
Boiler pressure16 kg/cm2 (15.7 bar; 228 psi)
Heating surface237 m2 (2,550 sq ft)
Superheater:
  Heating area112 m2 (1,210 sq ft)
Cylinders Four, simple
Cylinder size 450 mm × 680 mm (17+1116 in × 26+34 in)
Valve gear Walschaerts
Performance figures
Maximum speed130 km/h (81 mph)
Power output1,750 CV (1,290 kW; 1,730 hp)
Tractive effort 14,500 kgf (142 kN; 32,000 lbf)
Career
Operators Ferrovie dello Stato
Numbers691.001 – 691.033
WithdrawnEarly 1960s
PreservedOne: 691.022

The Ferrovie dello Stato Italiane (FS; Italian State Railways) Class 691 (Italian : Gruppo 691) is a class of 4-6-2 'Pacific' locomotives; they were the fastest and most powerful steam locomotives ever built for the Italian railways.

Contents

Origin

By the end of the 1920s the FS were considering the possibility of building a new class of Pacific locomotives for mainline express duties; the existing Class 690 ones were poor steamers (because of the small firebox) and therefore not being successful (with the much lighter Class S.685 2-6-2 locomotives having the same performance as them). This class, which should have been the Class 695, would have had however a very high axle load (as much as 21 tonnes (21 long tons; 23 short tons)), which would have required strengthening of the lines they were supposed to serve; as electrification was becoming more and more prominent, such an expense was considered unwarranted. Therefore, a less ambitious plan, which involved rebuilding the Class 690 locomotives (and which would have entailed a lower axle load), was approved. [1]

The boiler of the Class 690 was replaced by the one fitted on the Class 746 locomotives; the trailing axle was replaced by a Bissel truck, to sustain the weight of the new, larger firebox, and a Nielebock-Knorr pre-heater was added. [2] The 33 locomotives were rebuilt, part by the FS workshops, and part by the Ernesto Breda company. Initially, they would have received the same tender designed for the Class 695, but in the end an enlarged version of the standard FS bogie tender was fitted.

Operation

The Class 691 served on the Milan-Bologna (up to 1938, when the line was electrified) and the Milan-Venice mainlines throughout their careers, pulling the heaviest and fastest express trains. Three of them were destroyed or irreparably damaged in the years of World War II. After the electrification of the Milan-Venice railway in the spring of 1957, some locomotives remained active for some time on the Venice-Cervignano del Friuli line, but by the early 1960s they were all withdrawn. [3]

The 691.011 scored the speed record, between the stations of Verona and Padova, for the Italian steam locomotives, with 150 kilometres per hour (93 mph). [4]

Modifications

In 1939, the 691.026 was given a streamlined casing, which was unsuccessful; by 1946 the casing had already been removed.

In 1943, the 691.004 was fitted with a smoke deflector with bad results.

Preservation

Only one locomotive of the class survived into preservation, the 691.022, which is a static exhibit at the Museo della Scienza e della Tecnologia "Leonardo da Vinci" in Milan.

Related Research Articles

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<span class="mw-page-title-main">FS Class 685</span> Italian class of railway locomotives

The Ferrovie dello Stato Class 685 is a class of 2-6-2 'Prairie' express train steam locomotives. These are colloquially known as Regine, mirroring their fame as one of the most successful and appreciated Italian steam locomotives.

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<span class="mw-page-title-main">FS Class 690 II</span>

The Ferrovie dello Stato Italiane Class 690 was a 4-6-2 'Pacific' steam locomotive for express trains.

<span class="mw-page-title-main">FS Class 746</span>

The Ferrovie dello Stato Italiane Class 746 is a class of 2-8-2 'Mikado' steam locomotive. These were the biggest steam locomotives ever built by the Ferrovie dello Stato, even though not the fastest, which were the Class 691s.

<span class="mw-page-title-main">FS Class 470</span>

The Ferrovie dello Stato Italiane Class 470 is a 0-10-0 steam locomotive.

<span class="mw-page-title-main">FS Class 480</span> Italian steam locomotive

The Ferrovie dello Stato Class 480 is a 2-10-0 steam locomotive.

<span class="mw-page-title-main">FS Class 650</span>

The Ferrovie dello Stato Italiane Class 650, formerly SFAI1181-1200 and Rete Mediterranea 300 Class, also known as "Vittorio Emanuele II", was the first steam locomotive in continental Europe to have the 4-6-0 'Ten-Wheeler' arrangement.

<span class="mw-page-title-main">FS Class 940</span>

The Ferrovie dello Stato Italiane Class 940 is a 2-8-2 steam tank locomotive, derived from the Class 740 tender locomotive.

<span class="mw-page-title-main">FS Class 680</span>

The Ferrovie dello Stato Italiane Class 680 is a 2-6-2 express steam locomotive; it was the direct ancestor of the very successful and appreciated Class 685.

<span class="mw-page-title-main">FS Class 552</span>

The Ferrovie dello Stato Italiane Class 552, formerly Rete Adriatica Class 180 bis, is a 4-4-0 steam locomotive; it was the final development in Italy of the 'American' express locomotive type.

<span class="mw-page-title-main">FS Class 600</span>

The Ferrovie dello Stato Italiane Class 600, formerly Rete Adriatica Class 380 and Società per le Strade Ferrate Meridionali Class 380, is a 2-6-0 'Mogul' steam locomotive; it is considered by some as the first Italian modern steam locomotive.

<span class="mw-page-title-main">FS Class 835</span>

The Ferrovie dello Stato Italiane Class 835 is a 0-6-0T steam locomotive; it was the standard steam shunter of the FS.

<span class="mw-page-title-main">FS Class 290</span>

The Ferrovie dello Stato Italiane Class 290, formerly the Rete Adriatica Class 350 bis, is a 0-6-0 steam locomotive.

<span class="mw-page-title-main">FS Class 741 II</span> Italian steam locomotive

The Ferrovie dello Stato Class 741 is a class of 2-8-0 'Consolidation' steam locomotives, rebuilds from the FS Class 740 with a Franco-Crosti boiler; it was the last class of steam locomotives introduced in Italy.

<span class="mw-page-title-main">FS Class 122</span>

FS Class 122 were 2-4-0 steam locomotives with tenders, designed for hauling passenger trains. The Italian State Railways (FS) acquired 32 of them as war reparations after World War I from the Austrian Südbahn (SB).

<span class="mw-page-title-main">FS Class 400</span>

FS Class 400 were steam locomotives of French construction, built for service in Italy. They were 0-8-0 tender locomotives with two outside cylinders.

<span class="mw-page-title-main">FS Class 910</span>

FS Class 910 were 2-6-2 tank locomotives designed by Guglielmo Cappa for Rete Sicula where they were registered as RS Class 400. They were absorbed by Italian State Railways (FS) in 1905 and became FS Class 910.

The Ferrovie dello Stato Class 745 was a class of 2-8-0 'Consolidation' steam locomotives.

<span class="mw-page-title-main">FS Class 744</span>

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References

  • Cornolò, Giovanni (July 2014). "Locomotive a Vapore". TuttoTreno (3).
  • Kalla-Bishop, P. M. (1986). Italian State Railways Steam Locomotives. Abingdon: Tourret Publishing. pp. 61–62. ISBN   0-905878-03-5.