Rome–Fiuggi–Alatri–Frosinone railway

It consisted of a 78.1 kilometers (48.5 mi) long narrow gauge 950 mm (3 ft 1+3⁄8 in) line from Rome to Fiuggi.

In March 1907, the Superior Council of Public Works gave its permission to build the line, which had been designed by Antonio Clementi.

The railway used a narrow gauge of 950 mm (3 ft 1+3⁄8 in), with electric traction and high-voltage direct current (850 V).

From Rome to Fiuggi trips lasted two hours and 45 minutes, but service was frequent, with a train departing every half-hour.

The Fiuggi-Alatri-Frosinone and Fiuggi-Vico nel Lazio-Guarcino branch lines were opened for service on 14 July 1917.