1893 (1st April) The Ozieri-Tirso line was inaugurated; on the same day the Mandas-Nurri and Gairo-Arbatax tracts were inaugurated; (16th November) the railway reached Villanovatulo on one side and Ussassai on the other; at the same time the Gairo branch up to Jerzu was inaugurated.
1894 (20th April) The entire 160 kilometre tract from Mandas to Arbatax was inaugurated.

SFSS possessed a total railway network of about 590 kilometres.

1912 (21st March) Royal Decree no. 684 was passed awarding the concession for the construction and management of the Isili-Villacidro railway with the Ales-Villamar branch to the "Società Ferrovie Complementari della Sardegna" (SFCS), under the management of the Sardinian engineers Gracco Tronci, Stanislao e Dionigi Scano.
1915 (21st June) The Isili-Villacidro with the Ales-Villamar branch was inaugurated.
1921 (1st January) The SFCS took over the SFSS.
1926 (23rd May) It was inaugurated in the Sulcis area the railway network of the "Società Ferrovie Meridionali Sarde" of 114 kilometres of length.

The north part of Sardinia was still insulated and badly served.

1927 (27th March) Royal Decree no. 656 was passed awarding the concession for the construction and management of the Sorso-Sassari-Tempio and Luras-Palau track sections to the "Società Ferrovie Settentrionali Sarde" (SFSS) under the management of engineer Diego Murgia.
1930 (12th May) The Sassari-Sorso line was inaugurated.
1931 (16th November) The Sassari-Tempio line was inaugurated.
1932 (18th January) The Luras-Palau line was inaugurated.