Doğuş-Özaltın–Yapı Merkezi Joint Venture had signed the contract on April 14, 2017 for the construction of ”Çekmeköy-Sancaktepe-Sultanbeyli and Sarıgazi-Taşdelen-Yenidoğan Metro Lines” which was tendered with an approximate contract value of 2.342 million TRY by the Directorate of Anatolian Side Rail System of Head of Rail System Department of Istanbul Metropolitan Municipality. However, the project had been suspended for 2 years due to financing issues.
The mayor of the Istanbul Metropolitan Municipality (İBB) Ekrem İmamoğlu made a declaration to the public on the recommencement of construction works of Çekmeköy-Sancaktepe-Sultanbeyli metro line, in the ceremony took place in Abdurrahmangazi Station on November 26, 2019. Senior management of Doğuş Construction, Yapı Merkezi ve Özaltın Construction participated in this ceremony where the Chairman of Doğuş Construction Hüsnü Akhan presented a plaque to the Mayor İmamoğlu.
The 10,9 km-long Sancaktepe-Sultanbeyli line as the extension of Üsküdar-Ümraniye-Çekmeköy Metro Line which was previously completed by Doğuş Construction as the sole contractor, will have 8 stations. While main tunnels of the lines will be excavated by a TBM, 663.145 m3 of open excavation and 539.251 m3 of excavation by NATM (The New Austrian Tunneling Method) will be performed.