The locomotive was designed to tackle steeply-graded lines, such as Messina - Palermo with its pass of the Peloritani Mountains and its long tunnel.

It also had to be suitable for minor local or commuter services and to have the characteristic of bidirectionality, to gain time at terminal stations by avoiding the need for turntables.

Over the years, they underwent small changes and continued to perform good service in the locomotive depots of Milano Centrale and Pavia for the service on the lines from Milan to Bergamo, Como, Lecco and Voghera.

The locomotive frame was carried on three coupled axles and two one-axle trucks, of the Adams type, at the two ends.

This made the locomotive stable, even at high speeds, both in forward and reverse.