The FS Class E.431 was a class of three-phase AC

electric locomotive An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or on-board energy storage such as a battery or a supercapacitor. Locomotives with on-board fuelled prime movers, such as diesel engines or gas ...

s of the

Italian State Railways Ferrovie dello Stato Italiane S.p.A. ( "Italian Railways of the State"; previously only Ferrovie dello Stato, hence the abbreviation FS) is Italy's national state-owned railway holding company that manages transport, infrastructure, real estate ...

(FS).

History

The E.431 was a class of 37 locomotives, built between 1922 and 1925 by

Tecnomasio Italiano-Brown-Boveri Tecnomasio was an Italian scientific and precision instrument company founded in the 1860s. By the beginning of the 20th century the company has begun to produce electrical equipment. After financial problems in the early 1900s the company was acq ...

(TIBB), divided into three batches, the last in collaboration with

Ansaldo Ansaldo Energia S.p.A. is an Italian power engineering company. It is based in Genoa, Italy. The absorbed parent company, Gio. Ansaldo & C., started in 1853. It was taken over by Leonardo S.p.A. In 2011, Leonardo S.p.A. sold 45% stake in An ...

. The locomotives were designed and constructed to be suitable for hauling heavy trains at , which, at the time, was considered the limit for the three-phase system. The extension of the electrified network with the three-phase system had come to involve the

regions In geography, regions, otherwise referred to as zones, lands or territories, are areas that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and the interaction of humanity and t ...

Piedmont it, Piemontese , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = , demographics1_footnotes = , demographics1_title1 = , demographics1_info1 = , demographics1_title2 ...

Liguria Liguria (; lij, Ligûria ; french: Ligurie) is a Regions of Italy, region of north-western Italy; its Capital city, capital is Genoa. Its territory is crossed by the Alps and the Apennine Mountains, Apennines Mountain chain, mountain range and is ...

and part of

Lombardy Lombardy ( it, Lombardia, Lombard language, Lombard: ''Lombardia'' or ''Lumbardia' '') is an administrative regions of Italy, region of Italy that covers ; it is located in the northern-central part of the country and has a population of about 10 ...

. This included the cities of

Turin Turin ( , Piedmontese language, Piedmontese: ; it, Torino ) is a city and an important business and cultural centre in Northern Italy. It is the capital city of Piedmont and of the Metropolitan City of Turin, and was the first Italian capital ...

Genoa Genoa ( ; it, Genova ; lij, Zêna ). is the capital of the Italian region of Liguria and the List of cities in Italy, sixth-largest city in Italy. In 2015, 594,733 people lived within the city's administrative limits. As of the 2011 Italian ce ...

and indirectly

Milan Milan ( , , Lombard: ; it, Milano ) is a city in northern Italy, capital of Lombardy, and the second-most populous city proper in Italy after Rome. The city proper has a population of about 1.4 million, while its metropolitan city h ...

. With associated lines, international transits were possible. These lines were used by fast and important international trains with heavy loads (up to 20 carriages) hence the need for machines suitable for this type of service. In practice, the E.431 did not live up to expectations. In particular, the cascade connection of the motors at the lower speeds gave insufficient tractive effort, affecting performance during starting and uphill travel. They were not, therefore, used on the Frejus and Brenner lines, while on the remaining climbs, in particular on those that lead from the Ligurian coast to the hinterland, they were always used in multiple. These problems were solved, even if not definitively, with Class E.432 which had different control systems. On the flat, the E.431s could show off their speed, hauling the trains for which they were designed, but even here they sometimes worked in multiple. Some attempts to improve performance when running in cascade mode were made during the early years of service but they were not very successful. With the conversion of the three-phase lines to

direct current Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...

operation, the E.431s were progressively withdrawn but some locomotives remained in service on local trains until the end of the three-phase system occurred in 1976.

Technical features

Mechanical part

The E.431 was the first three-phase locomotive for passenger trains to have four-axle drive, to increase the adhesive weight. Each end drive axle was linked to the adjacent carrier axle by a

Zara bogie A Krauss-Helmholtz bogie (''Krauss-Helmholtz-Lenkgestell'') is a mechanism used on steam locomotives and some electric locomotives to improve curve running. Operation The bogie comprises a carrying axle connected to a coupled axle via a sha ...

. This arrangement, also adopted in many other locomotives, allowed better curve registration given the generally tortuous route of the lines in Italy. The two motors drove through a triangular

connecting rod A connecting rod, also called a 'con rod', is the part of a piston engine which connects the piston to the crankshaft. Together with the crank, the connecting rod converts the reciprocating motion of the piston into the rotation of the cranksh ...

and horizontal

coupling rod A coupling rod or side rod connects the driving wheels of a locomotive. Steam locomotives in particular usually have them, but some diesel and electric locomotives, especially older ones and shunters, also have them. The coupling rods transfer t ...

s transmitted the motion from the driving axle to the coupled axles. The wheels were of the type used on

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the locomot ...

s, with balance weights and cranks at 90 degrees. On a sturdy frame there was a central cabin in which the two

traction motor A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric vehicle, electric or hydrogen vehicles, elevators or electric multiple unit. Traction motors are used in electrically powered rail vehicles (ele ...

s, which were dismountable from below, were placed. At the ends there were two short bonnets which contained the auxiliary equipment, including fans, rheostat, compressors and brake reservoirs, as well as a reversing switch for the selection of the direction of travel.

Electrical part

The electrical part consisted of two

s whose stators were switchable between six or eight poles. With the cascade connection, in which the current induced in the

rotor Rotor may refer to: Science and technology Engineering *Rotor (electric), the non-stationary part of an alternator or electric motor, operating with a stationary element so called the stator * Helicopter rotor, the rotary wing(s) of a rotorcraft ...

of one motor fed the

stator The stator is the stationary part of a rotary system, found in electric generators, electric motors, sirens, mud motors or biological rotors. Energy flows through a stator to or from the rotating component of the system. In an electric mot ...

of the other motor, both motors ran at half speed. The available speeds were: * Cascade connection, * Parallel connection, The current limitation during starting and switching was obtained through a

liquid rheostat A liquid rheostat or water rheostat or salt water rheostat is a type of variable resistor. This may be used as a dummy load or as a starting resistor for large slip ring motors. In the simplest form it consists of a tank containing brine or ot ...

containing a 2% solution of

sodium carbonate Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...

in water as

electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon dis ...

. The electrolyte was cooled by a heat exchanger which transferred heat to another liquid circuit containing fresh water. Current was picked up from the

overhead line An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, trolleybuses or trams. It is known variously as: * Overhead catenary * Overhead contact system (OCS) * Overhead equipmen ...

through two

trolley pole A trolley pole is a tapered cylindrical pole of wood or metal, used to transfer electricity from a "live" (electrified) overhead wire to the control and the electric traction motors of a tram or trolley bus. It is a type of current collector. Th ...

s with "spades" - a pattern common in three-phase locomotives of the time.

Multiple unit control

After the encouraging results obtained with the small-wheeled locomotives

FS Class E.551 The Ferrovie dello Stato, FS Class E.550 was a class of three-phase electric locomotive used in Italy, introduced in the 20th century, which remained in service until 1965. History In the wake of the success met by Three-phase AC railway electri ...

and

FS Class E.554 The FS Class E.550 was a class of three-phase electric locomotive used in Italy, introduced in the 20th century, which remained in service until 1965. History In the wake of the success met by three-phase electric locomotives on the Valtellina ...

, it was decided to extend the experiment with "Ligurian" multiple unit control to some large-wheeled locomotives. The locomotives chosen for the experiment included two Class E.333 and E.431.023 and 026. The chosen machines, modified in the early months of 1960, behaved well in multiple control, demonstrating the validity of the solution adopted. The success of the "Ligurian" multiple control led to the idea of adopting it as standard equipment on all three-phase locomotives, excluding only the oldest types. For Class E.431 the transformation of a further eight units was arranged, but it was only performed on two of them. These were E.431.018 and E.431.036. On this pair of locomotives, a high voltage coupling was added which allowed the second unit to operate with lowered trolleys, in order to avoid a speed limit imposed on double-traction locomotives on the Turin -

Fossano Fossano ( pms, Fossan) is a town and ''comune'' of Piedmont, northern Italy. It is the fourth largest town of the Province of Cuneo, after Cuneo, Alba and Bra. It lies on the main railway line from Turin to Cuneo and to Savona, and has a branch li ...

Ceva Ceva, the ancient Ceba, is a small Italian town in the province of Cuneo, region of Piedmont, east of Cuneo. It lies on the right bank of the Tanaro on a wedge of land between that river and the Cevetta stream. History In the pre-Roman period th ...

line.

Preservation

E.431.027 is exhibited at the

Savigliano Savigliano (Savijan in Piedmontese) is a ''comune'' of Piedmont, northern Italy, in the Province of Cuneo, about south of Turin by rail. It is home to ironworks, foundries, locomotive works (once owned by Fiat Ferroviaria, now by Alstom) and s ...

site of the Piedmont Railway Museum (MFP) and E.431.037 is in the Technical Museum of

Speyer Speyer (, older spelling ''Speier'', French: ''Spire,'' historical English: ''Spires''; pfl, Schbaija) is a city in Rhineland-Palatinate in Germany with approximately 50,000 inhabitants. Located on the left bank of the river Rhine, Speyer li ...

, in the

Rhineland-Palatinate Rhineland-Palatinate ( , ; german: link=no, Rheinland-Pfalz ; lb, Rheinland-Pfalz ; pfl, Rhoilond-Palz) is a western state of Germany. It covers and has about 4.05 million residents. It is the ninth largest and sixth most populous of the ...

References

* Mario Loria, Storia della trazione elettrica ferroviaria in Italia, Firenze, Giunti, 1971 * Erminio Mascherpa, Le nostre locomotive. F. S. E.431. Mezzo secolo di buon servizio, in Italmodel ferrovie, 25 (1974), n. 167, pp. 5752-5760 * Erminio Mascherpa, Il comando multiplo delle locomotive trifasi, in Italmodel ferrovie, 26 (1974), n. 177, pp. 6129-6135 * Erminio Mascherpa, Il comando multiplo delle locomotive trifasi, in Italmodel ferrovie, 26 (1974), n. 178, pp. 6165-6171 * Giovanni Cornolò, Claudio Pedrazzini, Locomotive elettriche, Parma, Ermanno Albertelli Editore, 1983 * Gianfranco Ferro, Locomotive E 431, il... "coccodrillo" italiano!, fascicolo fuori testo Locomotive trifasi in Tutto treno, 4 (1991), n. 34, pp. 9-8 * Giovanni Cornolò, Locomotive elettriche FS, Parma, Ermanno Albertelli, 1994, pp. 121–128 * José Banaudo, Michel Braun, A vent'anni dal trifase, Pinerolo, Alzani, 1996. In testa al frontespizio: Amici del trifase. pp. 28, 32-33, 46-48, 63-69. * Fernando Barenghi, Cinquant'anni di costruzione di locomotive elettriche nello stabilimento di Vado Ligure, in Rassegna tecnica TIBB, 19 (1958), n. 4, pp. 81-90. Ristampato in Le locomotive del Tecnomasio. Itinerario nella storia della trazione elettrica attraverso 1000 locomotive, Vado Ligure, ABB Tecnomasio, 1994, pp. 33-77 * Franco De Falco, Dalla 050 alla E.404, in Le locomotive del Tecnomasio. Itinerario nella storia della trazione elettrica attraverso 1000 locomotive, Vado Ligure, ABB Tecnomasio, 1994, pp. 9-21. Ristampato in Ingegneria ferroviaria, 67 (2012), n. 4, pp. 355-361 * Angelo Nascimbene, Aldo Riccardi, Ferrovie italiane anni '50. Seconda parte. Trazione elettrica, in Tutto treno tema, 9 (1996), n. 9, pp. ...-... * Nico Molino, E.431 FS. I levrieri del trifase, in Mondo ferroviario, (1999), n. 157, pp. 32-51 * Erminio Mascherpa, Quelle strane E.431, in I treni, 20 (1999), n. 206, pp. 18-24 * Giovanni Cornolò, Martin Gut, Ferrovie trifasi nel mondo. 1895-2000, Parma, Ermanno Albertelli, 2000, pp. 20–26, 121-145, 150-190, 265-271, 272-280, 529-530, 533-535 * David Jelerčič, Water Bellagente, Michele Mingari, Sui binari dei ricordi. Viaggio in Castano e Isabella, Milano, ACME, 2004 * Giovanni Cornolò, Dall'E.626 all'Eurostar. 1928-2008: ottant'anni di locomotive elettriche FS, Parma, Ermanno Albertelli, 2008, pp. pp. 29–32, 38, 44, 495-509 * Michele Mìngari, Gian Franco Ferro, Franco Dell'Amico, Viaggio in trifase. 75 anni di corrente alternata FS, Milano, ACME, 2009, pp. 36, 38-39, 42-43, 62-63, 188-189 * Alessandro Mandelli, Trifase alle Cinque Terre, in Tutto treno & storia, 10 (2010), n. 24, pp. ...-... * Michele Mingari, Velociste del trifase, in I treni, 33 (2012), n. 348, pp. 26-31 * Michele Mingari, Velociste del trifase, in I treni, 33 (2012), n. 349, pp. 14-21 * Gianfranco Ferro, Locomotive Gruppo E431 FS, in Tutto treno, 24 (2012), n. 263, pp. 22-31 * Gianfranco Ferro, Locomotive Gruppo E431 FS, in Tutto treno, 24 (2012), n. 266, pp. 16-25 * Angelo Nascimbene, In treno con le E 431, in Tutto treno e storia, (2013), n. 28, pp. 26-33 * Claudio Pedrazzini, Storia dell'elettrificazione e dei locomotori trifasi FS, Brescia, Club Fermodellistico Bresciano, 2017, {{FS locos E.431 Three-phase AC locomotives 1′D1′ locomotives Standard gauge locomotives of Italy Gio. Ansaldo & C. locomotives Freight locomotives