Trieste to Monterotondo trains might be a good value for money solution: travelling in Italy by train is often rather cheap and faster than taking a bus indeed Trains leave from Trieste Centrale and arrive at Monterotondo-Mentana every 60 minutes on average. If travelling with Trenitalia, you need to know the Trieste to Monterotondo train schedule: the first train leaves at 05:15, while the last ride is at 17:15. A Trieste to Monterotondo train cost about 86.8 €. But how long is the train ride from Trieste to Monterotondo? Your journey takes about 7 hours on average.