Italian three-phase electric E.331 class loco

FS loco 331.008 on the 19:50 Paris Gare de Lyon - Roma train at Bussoleno, Italy, 1 September 1952. This was a class of 18 built by Breda/Brown Boveri between 1914 and 1919 and used until 1963. They were fed from overhead at 3,600 Volts at 16.7 Hz.

It was structurally derived from the almost simultaneous E.330 which used a new pole-changing system and an increase in the number of stages to four achieving an economic locomotive speed. Until a few years previously only two speeds were possible with the arrangement of the drive motors in cascade or in parallel; however, the E.331 was built to obtain the different speeds with the only variation in the number of poles. Changing the number of poles also realized the change of the rotation speed. One of the limits of the locomotive and a source of numerous failures was the kind of rotary dialer that was applied to achieve the variations in the number of poles of the two traction motors.

The E.331 found employment between Turin and Bussoleno, on the Frejus line, for some time.

Axle arrangement 2-C-2, 100 km/h top speed; power around 2,000 kW; service weight 92 tonnes.

Due to the limited protection of internal electrical devices, allowing accidental contact with high voltage parts, these locomotives were nicknamed "assassine" (killers).