The railway traffic is snarled by some 200 commuters which occupied the tracks at Rome's second largest train station on Monday, officials said.
The group were asked to get off the train at Rome's Tiburtina station because they had not paid enough to get to their destination, Milan, officials with the state-run Trenitalia said.
The commuters travel weekly from Naples and surrounding areas, where their families live, to the north of Italy, where they work, according to new reports.
The protesters say the ticket is too expensive for them to pay every week and want the railway company to restore a discount previously granted to commuters, the reports said. A second-class ticket from Naples to Milan is about EUR55 (US$74).
Two train runs from Florence had to be diverted, and others were delayed by a few hours.