Athens–Piraeus Electric Railways 1869 as a steam train connecting Athens and its port, Piraeus, and was operated by Athens & Piraeus Railway Co ( or ). The project was considered important, so Queen Olga and the Prime Minister Thrasyvoulos Zaimis attended the inauguration ceremony. There were 8 trains in each direction daily and 9 trains in each direction on Sundays. In 1874 the Athens & Piraeus Railway Company was bought by the Bank of Industrial Credit (). Under the new ownership the railway procured additional rolling stock. Soon the line was extended to Omonoia Square with an underground section constructed with the cut-and-cover
Piraeus-Perama light railway at Methonis street, allowing freight trains to access Keratsini Port. At Keratsini a short branch was constructed leading to one of the jetties. Due to serious damages on infrastructure and rolling stock caused by Allied bombing of Piraeus on 11 January 1944 the line paused service until April 1945. Most of its time the line was exploited with two kind of regular services: one full length service from Piraeus to the Naval Base, running every 15 minutes with two car formation of the rolling stock (line number 4) and in between, 7,5 minutes after, a short service from Piraeus to