How it began
The Diolkos was built near Corinth at the end of the seventh or the beginning of the sixth century BCE, around the time when Periander was tyrant of the city. Its name comes from Greek words meaning across and portage machine. It crossed the Isthmus of Corinth, the neck of land that joins the Peloponnese to the rest of Greece, and it stayed in service from about 600 BCE until the middle of the first century CE.
Before it existed
A ship going between the Corinthian Gulf and the Saronic Gulf had to sail all the way around the Peloponnese. The route was long and it was dangerous, with gales around Cape Matapan and Cape Malea. A way of moving a vessel or its cargo across the few kilometers of the Isthmus avoided the whole voyage, which mattered to merchants and, in wartime, to fleets that needed to change seas quickly.
How it works
The track was paved with hard limestone, 3.4 to 6 meters wide, and estimates of its length run from 6 to 8.5 kilometers. Two parallel grooves about 1.6 meters apart ran along it and kept the wheels of the vehicles on course. Either the ship and its cargo went over on separate vehicles, or only the cargo crossed and was loaded onto another ship. Men and animals pulled with ropes and tackle, possibly with capstans. Thick ropes run from bow to stern kept the hulls from sagging.
What changed first
The written record is mostly of warships. In 428 BCE the Spartans planned to take ships over to threaten Athens, and in 411 BCE they carted a squadron across on its way to Chios. In 220 BCE Demetrius of Pharos had about fifty vessels dragged over, and three years later Philip V sent 38 across. In 31 BCE, after Actium, Octavian ordered part of his fleet of 260 light ships to be carried over the Isthmus.
What lasted
The historian M. J. T. Lewis called the Diolkos a railway in the basic sense: a prepared track that so guides the vehicles on it that they cannot leave it. Because it was open to all on payment, he counted it a public railway, an idea that did not return until about 1800. No other work of antiquity combined the guided track and the overland transport of ships on this scale.
Where it stands today
The Greek archaeologist Nikolaos Verdelis excavated the Diolkos between 1956 and 1962 and traced about 1,100 meters in all. Wash from ships in the nearby Corinth Canal has since eroded considerable portions, above all at the excavated western end. Restoration work in October 2024 shored up the canal bank and edged the track with earth and stone, and by July 2025 a footpath alongside that stretch was open.
