Berlin–Palermo railway axis in the context of Trans-European high-speed rail network

The Florence–Rome high-speed railway line is a link in the Italian high-speed rail network. It is known as the ferrovia direttissima Firenze–Roma in Italian—meaning "most direct Florence–Rome railway" (abbreviated DD); this name reflects the naming of the Rome–Formia–Naples Direttissima opened in 1927 and the Bologna–Florence Direttissima opened in 1934. The line was the first high-speed line opened in Europe when more than half of it opened on 24 February 1977. It was completed on 26 May 1992, reducing the time of the fastest trains between the two cities to 1 hour and 20 minutes. The old line is referred to by Ferrovie dello Stato (the State Railways) as the Linea Lenta (meaning "slow line", abbreviated LL) to distinguish it from the parallel high-speed line.

In 2016 a contract was let for resignalling with ETCS level 2. The line is part of Corridor 1 of the European Union's Trans-European high-speed rail network, which connects Berlin and Palermo.