<sod>The M4 opened on 17 August 2012<ref>{{cite news |url=http://www.hurriyet.com.tr/ekonomi/21245391.asp |newspaper=[[Hürriyet]] |title=Yüzde 50 müjdesiyle geliyor |date=2012-08-17 |language=Turkish |accessdate=2013-11-16 }}</ref> with a large ceremony in Kadıköy, in which [[Recep Tayyip Erdoğan]] personally took part in. On 29 October 2013, with the opening of [[Marmaray]] rail service under the [[Bosphorus]], [[Ayrılıkçeşmesi, Kadıköy|Ayrılık Çeşmesi]] station was opened to allow passengers to transfer between lines.<ref>{{cite web |url=http://www.emlakkulisi.com/guncel/kadikoy-kartal-metrosu-ayrilikcesme-istasyonu-ihalesi/64336 |publisher=Emlak Kulisi |title=Kadıköy - Kartal Metrosu Ayrılıkçeşme İstasyonu ihalesi |date=2012-07-11 |language=Turkish |accessdate=2013-11-16 }}</ref><ref>{{cite journal |url=http://www.railwaygazette.com/news/single-view/view/marmaray-tunnel-opens-to-link-europe-with-asia.html |title=Marmaray tunnel opens to link Europe with Asia |journal=[[Railway Gazette International]] |date=29 October 2013  |accessdate=4 October 2015}}</ref><eod>
<sod>The M4 opened on 17 August 2012<ref>{{cite news |url=http://www.hurriyet.com.tr/ekonomi/21245391.asp |newspaper=[[Hürriyet]] |title=Yüzde 50 müjdesiyle geliyor |date=2012-08-17 |language=Turkish |accessdate=2013-11-16 }}</ref> with a large ceremony in Kadıköy, in which [[Recep Tayyip Erdoğan]] personally took part in. On 29 October 2013, with the opening of [[Marmaray]] rail service under the [[Bosphorus]], [[Ayrılıkçeşmesi, Kadıköy|Ayrılık Çeşmesi]] station was opened to allow passengers to transfer between lines.<ref>{{cite web |url=http://www.emlakkulisi.com/guncel/kadikoy-kartal-metrosu-ayrilikcesme-istasyonu-ihalesi/64336 |publisher=Emlak Kulisi |title=Kadıköy - Kartal Metrosu Ayrılıkçeşme İstasyonu ihalesi |date=2012-07-11 |language=Turkish |accessdate=2013-11-16 }}</ref><ref>{{cite journal |url=http://www.railwaygazette.com/news/single-view/view/marmaray-tunnel-opens-to-link-europe-with-asia.html |title=Marmaray tunnel opens to link Europe with Asia |journal=[[Railway Gazette International]] |date=29 October 2013  |accessdate=4 October 2015}}</ref>On 10 October 2016, 3 new station added to the line (Yakacık Station, Pendik Station and Tavaşantepe Station). <ref>{{Cite web|url=http://www.ibb.istanbul/tr-TR/Pages/Haber.aspx?NewsID=23408|title=İstanbul Büyükşehir Belediyesi|website=www.ibb.istanbul|access-date=2016-10-10}}</ref><eod>