Rome–Formia–Naples railway

The Rome–Formia–Naples railway—also called the Rome–Naples Direttissima in Italian–is part of the traditional main north-south trunk line of the Italian railway network. It was opened in 1927 as a fast link as an alternative to the existing Rome–Naples via Cassino line, significantly reducing journey times. High-speed trains on the route use the parallel Rome–Naples high-speed railway, which was partially opened in December 2005, and fully in December 2009.

Source: Wikipedia