The TCDD passenger network in Turkey covers high-speed, mainline, regional, and selected urban rail corridors on state railway infrastructure. The YHT network is centered on Ankara and runs toward Istanbul through Eskisehir, toward Konya, and toward Sivas. Conventional mainline corridors extend from Ankara toward Kars, Izmir, Adana, and eastern Turkey, with regional services around areas such as Izmir, Adana, and central Anatolia. Major hub stations include Ankara Gar, Istanbul Sogutlucesme, Istanbul Halkali, Eskisehir, Konya, Sivas, Izmir Basmane, and Kars. Train categories include YHT high-speed trains, mainline intercity trains, regional trains, and Marmaray urban services in Istanbul.