FS Class E.331 was a class of

three-phase Three-phase electric power (abbreviated 3ϕ) is a common type of alternating current (AC) used in electricity generation, Electric power transmission, transmission, and Electric power distribution, distribution. It is a type of polyphase system ...

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 (electricity), battery or a supercapacitor. Locomotives with on-board fuelled prime mover (locomotive), ...

s of the

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

. Eighteen of these

2′C2′ Rigid-framed electric locomotives were some of the first generations of electric locomotive design. When these began the traction motors of these early locomotives, particularly with AC motors, were too large and heavy to be mounted directly to t ...

locomotives were built between 1914 and 1919 by

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and

Brown-Boveri Brown, Boveri & Cie. (Brown, Boveri & Company; BBC) was a Swiss group of electrical engineering companies. It was founded in Baden bei Zürich, in 1891 by Charles Eugene Lancelot Brown and Walter Boveri who worked at the Maschinenfabrik Oerlik ...

Overview

Eighteen of these locomotives were built by

, with electrical parts by

, between 1914 and 1919. The class had the same pole-changing system as the E.330 which allowed an increase in the number of economic speeds to four. Until a few years earlier, only two speeds could be obtained with the arrangement of

cascade Cascade, or Cascading may refer to: Science and technology Science * Air shower (physics), a cascade (particle shower) of subatomic particles and ionized nuclei ** Particle shower, a cascade of secondary particles produced as the result of a high ...

or parallel

traction motor A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric vehicle, electric or hydrogen vehicles, or electric multiple unit trains. Traction (engineering), Traction motors are used in electrically powe ...

connections. In the E.331, a further two economic speeds could be obtained by changing the number of poles on the traction motors. One of the limitations of the machine, and the source of numerous failures, was the type of rotary switch used to vary the number of poles. Current was picked up from the two-wire

overhead line An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, Electric multiple unit, electric multiple units, trolleybuses or trams. The generic term used by the International Union ...

by two pantographs, both continuously in use. The locomotive was built on a rigid frame, with three coupled axles driven by two

jackshaft A jackshaft, also called a countershaft, is a common mechanical design component used to transfer or synchronize rotational force in a machine. A jackshaft is often just a short stub with supporting bearings on the ends and two pulleys, gears ...

s connected to the motors by inclined

connecting rod A connecting rod, also called a 'con rod', is the part of a reciprocating engine, piston engine which connects the piston to the crankshaft. Together with the crank (mechanism), crank, the connecting rod converts the reciprocating motion of the p ...

s. The front and rear

bogie A bogie ( ) (or truck in North American English) comprises two or more Wheelset (rail transport), wheelsets (two Railroad wheel, wheels on an axle), in a frame, attached under a vehicle by a pivot. Bogies take various forms in various modes ...

s had smaller diameter wheels, as was usual for the locomotives of the time.

Service

Class E.331 locomotives were used between

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and Bussoleno, on the Frejus line. The 2′C2′ machines, with maximum speed and power of about , were at their ease, especially on the flat or on gentle gradients.

Overview

Service

References

Further reading