Power is provided by an Overhead Contract System with 25 kV AC, 50 Hz[8][9] In 2001, the infrastructure element of OSE was created, known as GAIAOSE.

[10] In 2003, OSE launched "Proastiakos SA", as a subsidiary to serve the operation of the suburban network in the urban complex of Athens during the 2004 Olympic Games.

[14] On 14 July 2016, the privatisation agency accepted Ferrovie dello Stato Italiane's offer, worth 45 million euros, to buy 100% of TrainOSE.

The approximate length of the active network in permanent operation reaches 1,800 kilometres (1,100 mi)[17] On the 5 September 2023, Storm Daniel[18] triggered largescale flooding in Thessaly.

[20] OSE engineers were on the ground in the worst affected areas Domokos, Doxaras, and Paleofarsalos to assess the extent of the damage, and prepare detailed reports, and seek financial assistance from the European Union.

[23] OSE managing director, Panagiotis Terezakis, spoke of reconstruction works reaching 50 million euros, confirming at the same time that there will be no rail traffic in the effected sections of the network for at least a month.

[24] The devastation goes beyond the tracks and signalling, affecting costly equipment such as the European Train Control System (ETCS), which enhances rail safety.

However services between Larissa and Volos remain suspended across Thessaly’s coast until the track is repaired, with a rail-replacement bus in operation.

The original logo depicted a winged wheel, symbolizing speed, mobility, and the connection between technology and transportation, a common motif in railway insignias worldwide.

This design was framed in a circular layout, often accompanied by the acronym "OSE" in Greek letters (ΟΣΕ) or full name in some instances.

Steam Locomotives, where primarily black with white or silver detailing, consistent with global practices for visibility and maintenance ease.

The letters of the new logo incorporate interlocking and flowing curves, symbolizing connection and movement, which align with the concept of a railway network.

High-speed Intercity (IC) trains were branded with more vibrant and passenger-focused liveries, including combinations of blue, white, and silver.

With the privatization of the passenger operator TRENOSE (now Hellenic Train under the Ferrovie dello Stato Italiane group), livery styles began to diversify.

[30] Specifically, on 29 November 2010, EDISY S.A. was merged back into the parent company OSE S.A., which is today the manager of the rail infrastructure of Greece.

This railway line, 620 km long, joins Thessaloniki via the Port of Alexandroupoli to Svilengrad in Bulgaria, passing through or near most major cities of East Macedonia and Thrace (Serres, Drama, Xanthi, Komotini).

The line section from Stavroupoli to Toxotes runs along Nestos River Valley and is part of a preserved area that is not accessible by road.

From Velestino it descends rapidly to the port of Volos, initially running parallel to the abandoned metre gauge line and then diverging through Melissiatika.

The West Thessaly single-track line to Kalabaka, recently converted to 1,435 mm (4 ft 8+1⁄2 in) standard gauge, branches off the Athens–Thessaloniki mainline at Palaiopharsalos.

The Peloponnese network belonged since its construction to the former Piraeus, Athens and Peloponnese Railways or SPAP (Greek: Σιδηρόδρομοι Πειραιώς Αθηνών Πελοποννήσου, Sidiródromi Pireós Athinón Peloponnísou; ΣΠΑΠ) until 1962 when they were merged to Hellenic State Railways or SEK (Greek: Σιδηρόδρομοι Ελληνικού Κράτους, Sidiródromi Ellinikoú Krátous; ΣΕΚ).

After Ano Liosia, the line runs north and west of the Aegaleo mountain range into Eleusis and onwards to the Megara plain.

The 1,000 mm (3 ft 3+3⁄8 in) metre gauge line to Patras runs through attractive scenery along the south side of the Gulf of Corinth, the northern coast of the Peloponnese.

The train runs to the east of Akti Dymaion and alongside the Gulf of Patras between the old and the new highways as far as Kato Achaia, where it passes along the bed of the ravine, 4 km from GR-9/E55 to Lappa.

It passes Pyrgos to the north, shortly branching left to the south west, leaving the main line for Kyparissia and Kalamata.

Another 13 km branch line, originally operated by a separate company Σιδηρόδρομος Πύργου–Κατακώλου (Pyrgos–Katakolo Railway), opened in 1883 to link Pyrgos with the port of Katakolo.

The line runs along the bed of the Alpheus river, east of GR-9/E55, then through Zacharo and into the plain westward with a few forested hills northwest of Kaiafa.

Located on the northern Peloponnese, it runs 22 km from Diakofto through the Vouraikos Gorge and the Mega Spilaion monastery and up to Kalavryta, stopping en route at Zachlorou.

EMOS now operates a Linke-Hoffman DMU on loan from OSE, an old Nippon Saryo diesel locomotive, formerly of Aliveri Lignite Mines and various rail cars.

[39] This 16-kilometre-long (9.9 mi) branch line, part of the SPAP network, served the port of Kyllini, from which ferries sail to Zakynthos Island.

Most accidents are due to level crossings, people walking near the tracks, bad communication and safety systems and uneducated workers.