The train is caled Circumvesuviana. At the Naples' Centrale Station, follow signs downstairs for the Circumvesuviana. There's a long corridor in the basement, and the ticket windows are to your left. Ask which track you will need. After you buy your tickets, follow the signs down another long corridor that has the turnstiles at the end. Insert your ticket. The platforms are just beyond. Be careful when getting on the circumvesuviana trains, different trains use the same track....the digital board will tell you what train is coming in next, be patient and wait until you see the Pompei Scavi one.
The Circumvesuvia costs E3.20 one way.
Many thanks to you both . can u tell me is the station at naples close to the docks.
Just to follow up what A of N has said please be ultra careful as Naples station and particularly the circumvesuviana one is renown for pick-pockets and scam artists. The trains are not the most comfortable but run on time. I think the entrance fee is €11 but EU citizens over 65 get in free (you must take proof like your passport) You can buy plenty of fruit at the entrance at a good price but take plenty of water in summer as it gets very hot, it's agreat trip although I prefer Herculaneum (Ercolano) Neil.