The Athens–Piraeus Electric Railways (Greek: Ηλεκτρικοί Σιδηρόδρομοι Αθηνών Πειραιώς, romanized: Ilektrikoi Sidirodromoi Athinon Peiraios, ΗΣΑΠ), commonly abbreviated as ISAP, was a company which operated the Piraeus - Kifissia line from 1 January 1976 to 17 June 2011.

The project was considered important, so Queen Olga and the Prime Minister Thrasyvoulos Zaimis attended the inauguration ceremony.

In 1874 the Athens & Piraeus Railway Company was bought by the Bank of Industrial Credit (Greek: Τράπεζα Βιομηχανικής Πίστεως).

[2] In 1926 the sister company Ilektriki Etaireia Metaforon or H.E.M., also part of Power Group, took over the 1,000 mm (3 ft 3+3⁄8 in) metre gauge Lavrion Square-Strofyli railway.

[5] In March 2011, the Greek Government passed Law 3920[6] to allow ISAP and Athens Tram to be absorbed by Attiko Metro Operations Company (AMEL).

It is built to 1,435 mm (4 ft 8+1⁄2 in) standard gauge and is electrified using the 750 V DC, third rail, top contact system, also used by Athens Metro Lines 2 and 3.

From Attiki the line continues north, following the alignment of the old Lavrion Square-Strofyli railway through Patissia, the suburbs of Nea Ionia, Irakleio, Marousi and terminates at Kifissia.

only a short train of two wooden railcars is preserved, modified with the addition of Scharfenberg couplers at each end and is displayed during special events.

The first generation rolling stock was numbered as in the following table:[8] The fifth (1951), sixth (1958) and seventh (1968) batches were of steel construction, made by Siemens-MAN.

During 1981-1984 ISAP leased six four-car, bright yellow trains of narrow loading gauge (type G-I or Gisela) from East Berlin's metro.