Hellenic State Railways or SEK (Greek: Σιδηρόδρομοι Ελληνικού Κράτους, Sidirodromi Ellinikou Kratous; Σ.Ε.Κ.) was a Greek public sector entity (legal person of public law, Greek: Ν.Π.Δ.Δ.) which was established in 1920 and operated most Greek railway lines until 1970. Greece became independent in 1832, the birth of the newly formed sovereign state coinciding with the start of the railway era. By 1835 plans were being put to the Greek state to construct a railway line from Athens to the port of Piraeus. 22 years later, in 1857, a contract for its construction was signed and the work commenced. It took four different companies a further twelve years to lay the 8.8 kilometres of track, the work being completed in 1869.
The social and economic structure of Greece towards the end of the 19th century was founded on the collection of small agricultural towns acting as marketplaces and economic centres for the villages that surrounded them. Back then Greece had very little industry and few roads, which made the government think about the development of a railway system that would go towards addressing the lack of internal and external communication that existed. In 1881 the Prime Minister, Alexandros Koumoundouros signed four contracts for the laying of 1,435 mm (4 ft 8 1⁄2 in) Standard gauge lines, with the intention of making Greece a pivotal point on the journey between Europe, India and Asia.The railways of Greece have a complex history which begin in 1869, with the completion of the then Athens & Piraeus Railway, with parts of it also becoming the second-
Greece is a member of the International Union of Railways (UIC). The UIC Country Code for Greece is 73.