On the European side of the Bosporus, the 13.3km Ataköy - Ikitelli line will connect an interchange with Turkish State Railways' (TCDD) Marmaray line at Ataköy with the districts of Bahcelievler, Bagcilar, and Basaksehir. The journey time between the two termini will be 19.5 minutes and the 12-station line will have capacity to carry 45,000 passengers per hour per direction (pphpd). The closing date for expressions of interest is September 14.
On the Asian side of the city, the 14.3km Dudullu - Bostanci line will connect the districts of Ümraniye, Ataşehir, and Kadiköy, interchanging with the lines M4 and M5, Marmaray, and the ferry terminal at Bostanci. The 13-station line will have a maximum capacity of 45,000 pphpd and a journey time of 21 minutes between the terminus stations. As part of the project a depot will be constructed at Dudullu. The deadline for expressions of interest is September 10.