We want to go to Herculaneum from the port of Naples. In 2019, I recall seeing a tram station under construction near the port. Can you take the tram to the Porta Nolana train station? thanks!
No. You need to take the Circumvesuviana or the Campania Express. Same tracks, different quality of ride.
tram station under construction
It is a metro station called Municipio and it's finished. There you can take an M1 train to Piazza Garibaldi, where there is the Circumvesuviana station. Half of the Circumvesuviana Trains from Piazza Garibaldi go to Herculaneum, Pompeii and Sorrento.
Close to the port there is an underground light rail station that's more or less finished, but still closed. Even if they had inaugurated the new service the trains would run west, towards the wrong volcano!