MAJOR ENGINEERING WORK...
Istanbul Haydarpasa station closed to mainline trains until 2015...
Major railway rebuilding work in connection with the new Bosporus Rail Tunnel project & Istanbul-Ankara high-speed line project means that no trains at all are running between Istanbul Haydarpasa and anywhere in Asian Turkey. Only suburban trains are currently using Haydarpasa station.
So how do you travel? You'll need to take a bus between Istanbul and Arifiye or Eskisehir. Or the Istanbul-Bursa ferry, and the bus+high-speed train combo from Bursa to Ankara.
When will it end? This situation will last until early 2014, when (at least according to the plan) high-speed trains to Ankara are due to start running from a station called Pendik, 25km east of Istanbul. A year or two later trains will finally link central Istanbul with Ankara once more, potentially using the new Bosphorus rail tunnel serving a new station in central Istanbul on the European side of the Bosphorus. High-speed trains will then link Istanbul with Ankara and Konya in record time.
Unaffected routes: Trains are STILL RUNNING between Ankara & Izmir, Ankara & Eskisehir, Ankara & Kayseri/Kars/Erzurum/Eastern Turkey, Ankara & Adana, Ankara & Konya, also between Bandirma & Izmir in connection with the Istanbul-Bandirma ferry.