Line 4, mostly known as the Cumana railway (Italian: Ferrovia Cumana) is a commuter rail service in Campania, southern Italy, connecting Naples by two separate routes with Torregaveta, near Cuma in the town of Bacoli (about 15 km west of Naples).

The line was opened on 1 July 1889 by the Società per le Ferrovie Napoletane;[1] the route follows the coast for about 20 km from the main terminal in the populous downtown area of Montesanto to Torregaveta via the stations of Corso Vittorio Emanuele, Fuorigrotta, Mostra, Bagnoli, Pozzuoli, Arco Felice, Baia and Fusaro.

In 1927, the railway, because of the increasing commuter traffic, was electrified with a 1,2 kV DC overhead line.

In the same year, the SFN gave the line to the SEPSA, a branch of the EAV.

From 6 to 20 April 2024, the completion works will be carried out which will allow the activation of the new route of the line between Gerolomini and Arco Felice, in order to complete the doubling of the line and allow the decommissioning of the old route.