[1] Designed in Florence for the Rete Adriatica by engineers such as Enrico Plancher and Giuseppe Zara, the Class 600 was meant to pull both passenger and freight trains on the steep and curvy Italian lines at a reasonable speed.

It introduced several novelties in Italian locomotive practice, the most notable of which is undoubtedly the Italian bogie: a derivation of the German Krauss-Helmholtz bogie, it was meant to ensure good performance in curves without requiring a four-wheel bogie; it proved very successful, and it would become a staple of Italian steam locomotives.

[4] Some of the first locomotives were numbered under the RA and the SFM (Strade Ferrate Meridionali) ownership, until they were absorbed by the Ferrovie dello Stato respectively in 1905 and 1906; two more, built for the Valsugana valley railway, were taken over by the FS in 1912.

However, the experiment was not followed on, and it was preferred, starting from 1929, to outright convert the locomotives to Class 625 status.

[1][6] The remaining unrebuilt Class 600 locomotives were gradually withdrawn before 1940.