Trifase 50 — 50 Years Since the End of Three-Phase Electric Traction

Trifase 50: A journey through time in Acqui Terme

On May 23 and 24, 2026, Acqui Terme, a spa town in the province of Alessandria in the heart of Piedmont, hosts Trifase 50, the event through which the Fondazione FS Italiane celebrates fifty years since the end of three-phase electric traction in Italy. This is not a local festival or a traditional feast, but a major historical railway re-enactment that draws enthusiasts, families, and curious visitors from all over Italy.

Why Acqui Terme?

The choice of city is no coincidence: it was here that, on May 25, 1976, the three-phase power on the Ferrovie dello Stato network was switched off forever. That day, the last train powered by three-phase traction arrived in Acqui from Alessandria, pulled by the E.432.008 locomotive along with the E.431.003; at 9:48 AM, the power was cut, and shortly after, with the line converted, the E.656.026 departed using direct current. Acqui Terme is therefore the symbolic site for the conclusion of an era that lasted over seventy years.

A unique railway system

Three-phase traction, powered at 3,600 volts and 16 2/3 Hz, was created to overcome the limitations of steam on difficult mountain lines, where power was needed that steam locomotives could not provide. With the transition to 3,000-volt direct current, the Italian network was standardized, becoming more uniform and flexible. The history of three-phase power is a little-known but fundamental page of Italian engineering, and Trifase 50 tells this story to the general public.

What to see at the Movicentro

The heart of the event is the Movicentro, the former freight warehouse of the Acqui Terme station, transformed into an exhibition space for the occasion. Here, you will find a photographic exhibition on the evolution of Italian electric traction, a display of model trains, screenings of historical films, and a series of cultural meetings and conferences with representatives from the railway world and historical figures from the sector. The program also includes the presentation of the book A 50 anni dal Trifase and the unveiling of a commemorative plaque upon the arrival of the historic train.

The historic train

The most anticipated moment is the arrival of the historic train departing from Milan Centrale, stopping in Alessandria, and reaching Acqui Terme pulled by the three-phase locomotive E.431.027 from the Museo Ferroviario Piemontese, the true symbolic centerpiece of the re-enactment. Furthermore, throughout the spring and summer of 2026, an E.464 locomotive with a livery dedicated to the three-phase celebrations will circulate on tourist trains, spreading the memory of this anniversary across the network.