Hellenic State Railways or SEK (, Sidirodromi Ellinikou Kratous; Σ.Ε.Κ.) was a Greek public sector entity (legal person of public law, ) which was established in 1920 and operated most Greek railway lines until 1970. History The Hellenic State Railways took over the standard gauge railway line from Piraeus to Papapouli at the pre-1912 borders, the extension from Papapouli to Platy and most of the former Ottoman railway lines that were within the Greek borders after 1919. These lines were: Piraeus, Demerli & Frontiers Railway (), also known as Part of the former Thessaloniki & Monastir Railway ( or SM) Part of or CO, between Thessaloniki and Idomeni. The line from Alexandroupolis to Ormenio was transferred to the French-Hellenic Railway Company (, CFFH) of Evros ( or ) which was absorbed by SEK much later, in 1954 The Thessaloniki-Constantinople Link Railway ( or JSC) operating the Thessaloniki–Alexandroupolis railway. The 66 km long Sarakli-Stavros line, a former military line ( gauge) constructed during World War I (see also: Perivolaki – Nea Zichni railway line). The 50 km long Skydra local railway, a former military line ( gauge) constructed during World War I and initially operated until 1936 by a company called Local Railways of Macedonia (). After World War II the Hellenic State Railways absorbed most other Greek railways, including: Piraeus, Athens and Peloponnese Railways (1962), which had already absorbed other minor metre gauge railways. Thessaly Railways (1955), including Pelion railway. The French-Hellenic Railway Company (Chemin de fer Franco-Hellenique) of Evros (1954). Only Ellinikoi Ilektrikoi Sidirodromoi (E.I.S., later Athens-Piraeus Electric Railways), operator of Piraeus-Kifissia railway and Piraeus-Perama light railway, and the private mining and industrial lines remained independent. The Hellenic State Railways existed until December 31, 1970. On the next day all railways in Greece with the exception of private industrial lines and E.I.S. were transferred to Hellenic Railways Organisation S.A., a state-owned corporation. Network and other infrastructure During this period very little expansion of the existing network took place, the most notable being: The Amyntaio-Kozani branch (1955). The 15 km long line from to Kulata (1966), connecting the Greek and Bulgarian railway networks. Another 25 km long branch line from Nea Zichni (Mirini) to Amphipolis (1931), which was later abandoned and the track was lifted in 1970. Conversion of the line between Athens and Inoi to double track. A contract was signed in 1928 for a new line connecting Kalampaka