The first railway in Greece opened on 24th February, 1869, between Athens and Piraeus. It was built to standard (1435mm) gauge. The line was electrified in 1904.
Subsequent railway development in Greece was influenced by the complex and difficult topography of the country. A network of lines in standard and various narrow gauges grew up, in the hands of a multiplicity of companies. Those that survived wars and difficult economic conditions gradually came under the control of OSE, the Hellenic Railway Organization. An exception to this rule is the pioneering Athens Piraeus Electric Railway, which, although nationalised in 1976 and later rebranded as Line 1 of the Athens Metro, retains its separate identity.
The surviving narrow gauge lines of OSE have been converted to standard gauge, with a few exceptions: the metre gauge Patras Suburban Railway; the meter gauge line to Olimpia, which connects with cruise ships at Katakolo; the 750mm gauge rack railway from Diakopto to Kalvrita; and the 600mm gauge seasonal tourist service between Ano Lechonia and Milies.
The operating division of OSE was privatised in 2017 but the state retains ownership of the traction, rolling stock and infrastructure.
Flag image from CIA World Factbook