Line A4 is an Athens Suburban Railway (Proastiakos) line in Athens, Greece, managed by Hellenic Train. The service connects Piraeus with the coastal city of Kiato. The line shares a part of its course with lines A1 and A3 as well as Metro line 2, but also with line A3 at Ano Liosia. The first Suburban line was inaugurated on 30 July 2004, using 17 OSE Class 560 DMUs between Larissa Station and the Airport. With the completion of the electrification of the sections of the line to Athens in 2017 and Piraeus in 2018. The line now exclusively uses OSE class 460 EMUs rolling stock.