FS Class 745

Ferrovie dello Stato Italiane

Industry	Railway
Founded	1905
Headquarters	Italy

The FS Class 745 was a series of 2-8-0 'Consolidation' steam locomotives operated by the Ferrovie dello Stato Italiane (FS; Italian State Railways).

Design and construction

The Class 745 was developed to fulfill the requirement for a locomotive with a low axle load that could still deliver sufficient power on the Salerno–Reggio di Calabria railway. This route, characterized by sharp curves and steep gradients, gained strategic importance following the Italo-Turkish War of 1911–1912 but was limited by outdated infrastructure allowing a maximum axle load of only 14.4 tonnes. Existing locomotives like the FS Class 600 and FS Class 625, both with a 2-6-0 wheel arrangement, were increasingly inadequate for rising traffic demands, even when operated in tandem. Although the 2-8-0 FS Class 730 and FS Class 740 provided suitable tractive effort and maintained moderate axle loads, their top speeds were insufficient. Conversely, faster models such as the FS Class 680 and FS Class 685, featuring a 2-6-2 configuration, imposed excessive axle loads and lacked adequate pulling power. Consequently, designers concentrated on creating a 2-8-0 locomotive equipped with larger driving wheels and an ample boiler capacity.

The driving wheels measured 1,630 mm (64.17 in), matching those of the Class 625, and incorporated the distinctive Italian bogie design known as the Krauss-Helmholtz_bogie#Italian_bogie. The locomotive also adopted the unusual layout of two inside cylinders paired with external steam chests and valve gear to minimize overall weight. However, this compact configuration became a significant drawback: the short connecting rods linked to the second coupled axle caused frequent overheating issues in the bearings due to limited space. The tender was based on FS’s standard bogie design but featured a reduced water capacity of 18,000 litres (4,000 imp gal; 4,800 US gal) to accommodate the lightweight bridges along the route; this volume was later increased to the typical 22,000 litres (4,800 imp gal; 5,800 US gal) as infrastructure improvements were made.

Between 1913 and 1914, the initial dozen units were produced by Gio. Ansaldo & C. and Società Italiana Ernesto Breda. Following this, Ansaldo manufactured an additional 36 locomotives in 1919. The final series of 25 engines was completed between 1922 and 1923 by both companies, with this last group differing by having left-hand drive instead of right-hand drive as seen in earlier batches.

Operational history

The Class 745 significantly reduced the reliance on additional motive power along the Tyrrhenian railway, particularly on the steep 1-in-43.5 gradient between Agropoli and Vallo della Lucania, as well as on the route connecting Reggio Calabria and Taranto. However, over time, the heavier loads on the former route necessitated the use of double-heading for the most demanding trains. Consequently, the FS electrified this line in 1935 to address these challenges. Class 745 locomotives were allocated to depots including Ancona, Naples, and Udine; the units based in Udine were later reassigned to Padua until their withdrawal and scrapping in the mid-1960s. None of these locomotives have been preserved.

Bibliography

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