Hellenic State Railways
Former Greek state railway entity that operated most of the country's railway network from 1920 until its replacement by OSE at the end of 1970.
Last updated August 25, 2026
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Overview
Hellenic State Railways, commonly abbreviated as SEK, was the Greek public railway entity responsible for operating most of Greece's national railway system between 1920 and 1970. It was established on 18 March 1920 under Law 2144/20 as a legal person governed by public law. Its formation consolidated a fragmented railway landscape that had developed under several private, foreign, military, and regional operators, particularly as Greek territory expanded after the Balkan Wars and the First World War. SEK initially assumed control of the standard-gauge route from Piraeus through Athens and northward to Papapouli, together with the extension from Papapouli to Platy. It also took over Greek sections of several former Ottoman or internationally organized railway systems. These included portions of the Piraeus–Demerli–Frontiers Railway, better known as the Larisaikos; the former Thessaloniki–Monastir Railway; the Thessaloniki–Idomeni section of the Chemins de fer Orientaux; and the Thessaloniki–Alexandroupolis railway, historically associated with the Salonique–Constantinople Junction Railway. SEK also inherited several smaller or unusual lines, including narrow-gauge military railways built during the First World War around Sarakli–Stavros and Skydra. The organization gradually absorbed additional railway companies after the Second World War. Thessaly Railways became part of SEK in 1955, bringing the Pelion railway and other regional infrastructure into the state system. In 1954, SEK absorbed the French-Hellenic Railway Company operating in the Evros region. In 1962, it took over the Piraeus, Athens and Peloponnese Railways, which had previously consolidated a number of smaller metre-gauge systems. The principal exceptions were the electric railway operator E.I.S., which ran the Piraeus–Kifissia and Piraeus–Perama lines, and certain private industrial and mining railways. SEK's period of operation was marked more by rehabilitation and consolidation than by large-scale network expansion. Greek railway infrastructure and rolling stock suffered extensive damage during the Second World War, especially in 1943 and 1944, and the system did not return to full operation until 1950. Postwar work included rebuilding stations, restoring bridges and track, converting selected routes, and improving connections between regional lines. Notable developments included the Amyntaio–Kozani branch in 1955, the Strymonas–Kulata international connection in 1966, the conversion of the Larissa–Volos line to standard gauge in 1960, and the progressive doubling of the Athens–Inoi route. The company also presided over a major technological transition. Until the early 1960s, its locomotive fleet consisted largely of steam locomotives inherited from predecessor railways or acquired from varied foreign sources. Diesel traction began to replace steam in 1962, when SEK received Krupp shunters and Alco diesel locomotives. Diesel multiple units had already appeared in 1936 and became increasingly important during the 1950s and 1960s, while steam locomotives remained in limited service near the end of the company's life. SEK ceased to exist as the principal state railway entity on 31 December 1970. On 1 January 1971, nearly all Greek railway operations and infrastructure, apart from the independent electric railway and private industrial lines, were transferred to the newly established Hellenic Railways Organisation S.A., commonly known as OSE. SEK is therefore a historical predecessor of OSE rather than a continuing railway brand.
History
Hellenic State Railways was created during a period in which the Greek railway system was divided among several companies and administrative traditions. The state established SEK on 18 March 1920 through Law 2144/20, giving it the legal form of a public-law entity. Its initial purpose was to place the principal railway routes located within Greek territory under coordinated state administration. The first network transferred to SEK included the standard-gauge line from Piraeus to Papapouli, its continuation to Platy, and Greek sections of railways formerly connected with Ottoman or international railway enterprises. Among the inherited systems were the Piraeus–Demerli–Frontiers Railway, parts of the Thessaloniki–Monastir Railway, the Thessaloniki–Idomeni route associated with the Chemins de fer Orientaux, and the Thessaloniki–Alexandroupolis line. SEK also received smaller narrow-gauge routes, including the Sarakli–Stavros and Skydra lines, both of which had military origins dating from the First World War. The company's network expanded principally through absorption rather than through construction of entirely new routes. The French-Hellenic Railway Company in Evros was absorbed in 1954, and Thessaly Railways followed in 1955. The latter transfer brought regional lines around Thessaly and the Pelion railway under state control. In 1962, SEK absorbed the Piraeus, Athens and Peloponnese Railways, which had itself incorporated various smaller metre-gauge lines. The electric railway system operated by E.I.S. remained outside SEK, as did some private industrial and mining railways. World War II severely disrupted the railway system. Bridges, track, stations, and rolling stock were damaged, with particularly serious destruction occurring in 1943–1944. Although much of the system became operational again by 1950, some major reconstruction projects continued for years. The Achladokampos viaduct in the Peloponnese, destroyed in 1944, was not rebuilt until 1974, after SEK had already been replaced. During the postwar period, SEK undertook selective network improvements. A branch from Amyntaio to Kozani opened in 1955. The Larissa–Volos railway was converted from metre gauge to standard gauge in 1960, enabling it to connect with the Athens–Thessaloniki corridor at Larissa. A 15-kilometre line linking Strymonas with Kulata opened in 1966 and connected the Greek and Bulgarian networks. A branch from Nea Zichni to Amphipolis, opened in 1931, was later abandoned and its track removed in 1970. A proposed Kalampaka–Kozani line was contracted in 1928 but abandoned in 1932 because funding was unavailable. SEK also modernized its stations and motive power. New or substantially improved passenger stations were built at Thessaloniki, Larissa, Lianokladi, and numerous other locations. Steam traction remained important during the first decades of the organization, but the fleet became increasingly diverse because it included inherited locomotives, postwar foreign-aid equipment, and new purchases. Dieselization began decisively in 1962 with the arrival of Krupp shunters and Alco diesel locomotives. Diesel multiple units, first introduced in 1936, became more common in the 1950s and 1960s. Steam locomotives had not disappeared entirely by the end of 1970, but their role had narrowed considerably. The Hellenic State Railways ended operations on 31 December 1970. From 1 January 1971, the Greek state transferred almost all railway infrastructure and services under its control to Hellenic Railways Organisation S.A. OSE thus became the institutional successor to SEK. Because the transfer was a reorganization of the national railway system rather than a continuation of the same legal entity, SEK is treated as a historical railway organization and predecessor to modern Greek railway institutions.
- 1970
SEK is replaced by OSE
[1]SEK ceased to exist on 31 December 1970. From the following day, nearly all state railway operations and infrastructure were transferred to Hellenic Railways Organisation S.A.
- 1966
Strymonas–Kulata connection opens
[1]A 15-kilometre route between Strymonas and Kulata connected the Greek railway network with Bulgaria.
- 1962
Piraeus, Athens and Peloponnese Railways are absorbed
[1]SEK took over the Piraeus, Athens and Peloponnese Railways, further consolidating Greece's regional railway systems.
- 1962
Diesel locomotive modernization begins
[1]The first major diesel locomotive deliveries included Krupp Y60 shunters and Alco DL532B and DL500C locomotives.
- 1960
Larissa–Volos line is converted to standard gauge
[1]The former Thessaly Railways route between Larissa and Volos was converted to standard gauge and connected with the Athens–Thessaloniki railway at Larissa.
- 1955
Thessaly Railways joins SEK
[1]The state railway absorbed Thessaly Railways, including the Pelion railway and associated regional infrastructure.
- 1955
Amyntaio–Kozani branch opens
[1]SEK expanded its northern network with the opening of the Amyntaio–Kozani branch.
- 1954
French-Hellenic Railway Company is absorbed
[1]SEK absorbed the French-Hellenic Railway Company operating in the Evros region.
- 1950
Postwar railway system returns to full operation
[1]Following extensive wartime damage, the Greek railway system had been restored sufficiently to become fully operational again by 1950.
- 1936
Diesel multiple units enter service
[1]SEK introduced its first diesel multiple units, beginning a gradual shift away from exclusive reliance on locomotive-hauled steam services.
Products and positioning
State-owned national railway operator and consolidator of Greece's fragmented railway network
Passenger transportation · 1920
Passenger railway services
SEK operated passenger trains across Greece's principal standard-gauge routes and a range of regional metre-gauge and narrow-gauge lines. Its network linked Athens and Piraeus with Thessaloniki and other northern destinations, while absorbed regional systems extended service into Thessaly, the Peloponnese, Macedonia, and Thrace. Passenger operations used steam locomotives, diesel locomotives, and diesel multiple units during the company's later decades.
Freight transportation · 1920
Freight railway services
As the principal state railway operator, SEK provided freight transportation over the national network, serving industrial, agricultural, regional, and cross-border traffic. Freight work relied initially on inherited steam locomotives and later increasingly on diesel traction. The Strymonas–Kulata connection strengthened the network's international linkage with Bulgaria.
Railway rolling stock · 1962
Diesel locomotive fleet
SEK began significant dieselization in 1962. Early deliveries included 30 Krupp Y60 shunters classified as A-101, 10 Alco DL532B locomotives classified as A-201, and 10 Alco DL500C locomotives classified as A-301. Later classes served both standard-gauge and metre-gauge routes and gradually reduced the railway's dependence on steam power.
Railway rolling stock · 1936
Diesel multiple units
Diesel multiple units were introduced by SEK in 1936 and became more widespread during the 1950s and 1960s. The units supported passenger service on routes where self-propelled trains offered operational flexibility and lower requirements than traditional locomotive-hauled consists.
Brand decisions
1970
Transfer railway operations to OSEM&ABackground
The Greek state reorganized the institutional structure of its national railway system.
Action taken
On 31 December 1970, SEK was replaced by Hellenic Railways Organisation S.A., with almost all state railway infrastructure and operations transferred to the successor organization on 1 January 1971.
Aftermath
OSE became the continuing state railway organization, while E.I.S. and private industrial lines remained outside the transfer.
1962
Begin major conversion from steam to diesel tractionGeneration changeBackground
SEK operated a heterogeneous steam fleet assembled from predecessor networks and foreign sources.
Action taken
The railway accepted its first major group of diesel locomotives, including Krupp shunters and Alco road locomotives, while continuing to operate inherited steam equipment.
Aftermath
Diesel traction became increasingly important during the 1960s, although steam locomotives remained in limited use when SEK was dissolved.
1920
Create a unified state railway operatorStrategyBackground
Greece's railway system consisted of routes inherited from several private, foreign, regional, and military railway organizations.
Action taken
The Greek state established SEK as a public-law entity and assigned it responsibility for operating most railway lines within the country.
Aftermath
SEK became the central state railway organization and subsequently absorbed additional railway companies and regional systems.
Sources1 sources
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