There's an international regional train connection between Chiasso and Milan (Italy). This connection is a great option if you want to avoid reservation fees.
On the Eurail timetable RegioExpress trains are listed as "RE", and Regio trains as "R". InterCity trains are listed as "IC", and InterRegio trains as "IR". Regional and Intercity trains do not require seat reservations. Reservations are however recommended for Intercity trains during high season (May-September) and public holidays.
On the Eurail timetable ICE trains are shown as 'ICE', Railjet as "RJ", Eurocity as "EC" and TGV as 'TGV'. Reservations are compulsory for EuroCity and TGV. For ICE, RailJet and domestic ICN trains, reservations are optional but we recommend making reservations during weekends and busy periods.