Ankara Yenimahalle metro station. The Ankara Central Station is a major rail hub in Turkey. The Turkish State Railways operates passenger train service from Ankara to other major cities, such as: Istanbul, Eskişehir, Balıkesir, Kütahya, İzmir, Kayseri, Adana, Kars, Elâzığ, Malatya, Diyarbakır, Karabük, Zonguldak and Sivas. Commuter rail also runs between the stations of Sincan and Kayaş. On 13 March 2009, the new Yüksek Hızlı Tren (YHT) high-speed rail service began operation between Ankara and Eskişehir. On 23 August 2011, another YHT high-speed line commercially started its service between Ankara and Konya. On 25 July 2014, the Ankara–Istanbul high-speed line of
History of Ankara tetrarchy, a system of multiple (up to four) emperors introduced by Diocletian (284-305), seems to have engaged in a substantial programme of rebuilding and of road construction from Ankara westwards to Germe and Dorylaeum (now Eskişehir). In its heyday, Roman Ankara was a large market and trading center but it also functioned as a major administrative capital, where a high official ruled from the city's Praetorium, a large administrative palace or office. During the 3rd century, life in Ancyra, as in other Anatolian towns, seems to have become somewhat militarised in response to the invasions and instability of the town.