FS Class E.432

Società Ernesto Breda
Industry	Railway locomotive manufacturing
Founded	1886
Headquarters	Italy

Adapted from the English Wikipedia article FS Class E.432, available under CC BY-SA 4.0Updated 29 November 2025

Template:Infobox locomotive

FS Class E.432 represented a series of Three-phase AC railway electrification electric locomotives operated by the Italian State Railways. Constructed in 1928 by Società Ernesto Breda, a total of forty units with a UIC classification of 1′D1′ were produced, with two examples still preserved today.

History

Following the positive outcomes achieved through three-phase electrification, further expansion of the network demanded locomotives with enhanced capabilities. The earlier E.431 models did not meet expectations, prompting the State Railways' Traction Service around 1926 to initiate a new locomotive design project. Led by engineer Giuseppe Bianchi, the initiative sought to eliminate reliance on foreign patents concerning the pantographs, connecting rods, and motor-to-wheel transmission systems. Orders for these new locomotives were placed with Società Ernesto Breda in two separate batches totaling forty units. Beginning service in 1929, the E.432s operated on key routes such as the Porrettana and Brennero lines, later extending to connections between Turin and Genoa, including access to the Val di Susa and along the western stretches of the Liguria coast. These locomotives hauled the most significant and heaviest trains, including fast, direct, and international services. They frequently worked in pairs and occasionally coupled with other classes like the E.431 or E.333, while on steep gradients they were sometimes paired with smaller-wheel types such as the E.554. Additionally, they served local passenger trains.

With the transition of major routes to direct current electrification during the early 1960s, E.432 locomotives were reassigned primarily to depots in Savona and Cuneo. There, they spent their final years managing less demanding duties on trains running between Turin-Savona, Turin-Cuneo, and their associated branches. Notably, unit E.432.008 hauled a commemorative train from Alessandria to Acqui Terme on 25 May 1976, marking the conclusion of three-phase traction in Italy—a system that had been in use for over seventy-five years since its experimental beginnings.

Technical characteristics

Mechanical components

The E.432 locomotive featured a 1′D1′ wheel configuration with driving wheels measuring 1.63-metre (64 in) in diameter. The carrying wheels, designed to facilitate curve handling, were 1.11-metre (44 in) in diameter and mounted on Italian-style bogies. This model was engineered primarily for rapid and heavy passenger train operations.

Driving wheels were interconnected through coupling rods and powered by two traction motors via a distinctive articulated connecting rod created by Bianchi. To improve curve negotiation, sliding bearings were incorporated. The traction motors, fixed to the frame, could be removed from above for servicing. The wheels resembled those used on steam locomotives, equipped with balance weights and cranks positioned at right angles.

Positioned above the frame was a central driver's cab flanked by short bonnets at each end. One bonnet contained the liquid rheostat along with its pump and evaporative cooling system.

Electrical components

The electrical system comprised two substantial three-phase AC motors, each nearly two meters in diameter and weighing approximately twenty tonnes. Both motors had fans installed for forced air cooling. The electrical circuit allowed for cascade connection during startup and parallel connection for high-speed operation. Additionally, there were three armature wiring configurations enabling 12, 8, or 6 pole operation, providing four distinct speed settings: 37.5, 50, 75, and 100 km/h (23.3, 31.1, 46.6, and 62.1 mph). Switches to change pole configurations were housed in boxes above the motors. A liquid rheostat filled with a sodium carbonate solution helped limit current during both startup and pole switching phases. Connections were managed via a drum controller.

Around 1940, the cascade connection—which was seldom utilized—was discontinued. It proved more effective to commence movement at the second speed using the rheostat, minimizing reliance on high-voltage switching that often caused issues. Furthermore, motors tended to overheat under cascade connection conditions.

Power was collected through two double-sided pantographs mounted atop the cab roof; both pantographs operated simultaneously.

Multiple unit control

The proven effectiveness of the "Ligurian" multiple unit control system—previously tested on Classes E.551, E.554, E.333, and E.431—inspired plans to standardize it across all three-phase locomotives except for the oldest models. Conversion was intended for four E.432 units but ultimately completed on only one.

Initial candidates for conversion were E.432.002 and E.432.030. On these units—as well as on E.431.018 and E.431.036—it was planned to add high voltage coupling that would enable the trailing locomotive to operate with its pantographs lowered; however, implementation was postponed pending evaluation of results from the two E.431 conversions.

Meanwhile, labor union concerns arose due to fears of potential job losses linked to multiple unit operation. By the early 1960s, with three-phase traction being phased out on the Fréjus and Giovi routes, FS chose to halt the conversion program altogether. Consequently, only one E.432 locomotive—number 030—was equipped with the "Ligurian" multiple unit control system; although work began on E.432.002, its conversion remained incomplete.

Locomotive allocations

Initial

Locomotive depot in Bologna
Locomotive depot in Bolzano
Locomotive depot in Turin
Locomotive depot in Genoa

Subsequent

Locomotive depot in Savona
Locomotive depot in Cuneo

Starting from 1974

Locomotive depot in Alessandria

Preservation

Two units of this class have been preserved.

E 432.001 is housed at the National Railway Museum of Pietrarsa in Naples. This locomotive underwent restoration at the Cuneo depot workshop during 1988 and 1989.
E 432.031 is located at the Piedmontese Railway Museum in Savigliano, where it was receiving cosmetic restoration as of 2017.

References

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