The line from Piraeus to Thision was inaugurated on February 27, 1869 as a steam train connecting Athens and its port, Piraeus, and was operated by Athens & Piraeus Railway Co (Greek: Σιδηρόδρομος Αθηνών-Πειραιώς or Greek: Σ.Α.Π. Α.Ε.).
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 (Greek: Τράπεζα Βιομηχανικής Πίστεως).
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 method.

The line was electrified in 1904 using the 600 V DC, third rail, top contact system by Thomson Houston.
The line from Piraeus to Thision was inaugurated on February 27, 1869 as a steam train connecting Athens and its port, Piraeus, and was operated by Athens & Piraeus Railway Co (Greek: Σιδηρόδρομος Αθηνών-Πειραιώς or Greek: Σ.Α.Π. Α.Ε.). 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 (Greek: Τράπεζα Βιομηχανικής Πίστεως). 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 method.
The line was electrified in 1904 using the 600 V DC, third rail, top contact system by Thomson Houston.
Athens–Piraeus Electric Railways