Take the fast train, Frecciarossa, from Roma Termini to Naples. A one-way ticket costs about 45 euros and the journey takes around 70 minutes. Once you arrive at Napoli Centrale, head to the underground station for the Circumvesuviana train, which is clearly signposted. This train travels on the Naples to Sorrento line, stopping at various points including Herculaneum and Pompeii, and will take you closer to Vesuvius Ercolano Scavi station.
Last station: Ercolano Scavi station
Duration: 2 hours