Istanbul’s metro consists of two lines, the northern line connects Yenikapı to Hacıosman via Taksim Square and Mecidiyeköy and Levent.
There is also a funicular system connecting Taksim to Kabataş, where you can get on ferries and cross to the Anatolian side, and also transfer to trams bound for the old city.
The other funicular system, “Tünel”, runs between Karaköy and İstiklal Street. It is İstanbul’s first underground system, dating from 1875.
The separate southern Metro line connects Aksaray to Atatürk Airport, via the main bus station, Esenler Otogar. On the Asian side, the M4 metro line is now running and connects Kadıköy to Tavşantepe.
Click here for Istanbul’s Railway Network Map.