The State Railways of the Turkish Republic (Turkish: Türkiye Cumhuriyeti Devlet Demiryolları) or TCDD is the government owned, national railway carrier in the Republic of Turkey, headquartered in Ankara. The TCDD was formed on June 1, 1927 by the Turkish government to take over the administration of the existing rail lines within the borders of the Republic of Turkey after the dissolution of the Ottoman Empire, and to build new ones.
The Turkish State Railways own and operate all public railways in Turkey. As of 2008, TCDD controls 10,991 km (6,829 mi) of railways making it the 22nd largest railway system in the world. In 2009, TCDD carried 17,105,353 tonnes of freight and 7,118,699 passenger-
The Turkish State railways owns several other companies and holds shares in others, including İZBAN, a commuter railroad operating around İzmir, which TCDD has a 50% share in. These are all companies that are involved with rail transport or that use rail transport. TCDD is a member of InterRail since 1994. The Turkish Republic was proclaimed on 29 October 1923 and at once it undertook to revert the economic policies of the former Empire. In accordance with the ideas prevailing at that time, the Republic chose to force the country industrialization through a state program. Accordingly, a state railway company TCDD (Türkiye Cumhuriyeti Devlet Demiryolları) was founded in 1927 to take over railway development (law 1042 of 31 May 1927). The goal of the government was thus to ensure the creation of the infrastructure required for economic development, but also for the country's defense and the unity of the territory.