The E.326 was part of family of locomotives designed under engineer Giuseppe Bianchi in the 1920s and in 1930s for Italy's state railways, which, through the use of a great number of standardized components, would mean benefits such as reduced maintenance costs, easier repairs and more familiarity of the personnel.

[1] The FS ordered two prototypes from Società Italiana Ernesto Breda on 5 March 1929, which were outshopped respectively in July and December 1930.

In 1933 the FS designed another series of E.326, which would have sported smaller driving wheels (identical to those of the E.428) and modified auxiliaries, but the better performance of the E.428 and the ETR.200 project meant that they were not built.

[3] In April 1935 four locomotives were re-assigned to the Naples shed, for service on the new Rome-Naples line, and by July 1936 all twelve had been concentrated in Rome.

These issues, together with the increased availability of the E.428, and the appearance of the ETR.200 for long-distance express trains, meant that from 1936 the E.326 were largely relegated to secondary services, and were reassigned to Bologna.