The Rome–Fiuggi railway is a former railway built on the east part of Rome, Italy. It consisted of a 78.1 kilometers long narrow gauge 950 mm line from Rome to Fiuggi.
Wikipedia https://en.wikipedia.org/wiki/Rome–Fiuggi–Alatri–Frosinone_railway
Coordinates 41°49'32.267" N 12°54'56.03" E