Scheduled to leave from platform 4, and make a host of stops before
reaching Salerno, the 2nd class-only train number 21307, is operated
by Trenitalia as part of the Naples area Metropolitana system.
After Mergellina, it then runs underground for most of the trip thru'
the city - to emerge into the daylight again soon after leaving the
mezzanine platforms of the Piazza Garibaldi station, below the
mainline one known as 'Napoli Centrale'.
As singles, the tickets cost 4 Euro each.