Try googling it and look on you tube,,
we did it with a tour years ago,,,quite a sight,,but sad to see Pompei,,so many died and you can really see the destruction.
Not sure about train there,,,didnt see or hear about it at the time..
We didnt go "inside" volcano per se,,,but was quite strenuous walking ,,on uneven rocky ground and climbs.Was younger then and no problem...so assess your physical ability.
So,,if above helps you to "picture" it and looks good,,,I say go for it,,,know I ll never see that area again and glad I did. Sorry, can t give current info,,maybe others??