The Turkish State Railways (Turkish:Türk Devlet Demiryolları), abbreviated as TCDD, is a government-owned national railway company responsible for the ownership and maintenance of railways in Turkey, as well as the planning and construction of new lines. TCDD was formed on 4 June 1929 as part of the nationalisation of railways in Turkey.
The Turkish State Railways owns and maintains all public railways in Turkey. This includes railway stations, ports, bridges and tunnels, yards and maintenance facilities. In 2016, TCDD controlled an active network of 12,532 km (7,787 mi) of railways, making it the 22nd-largest railway system in the world. Apart from railway infrastructure, TCDD also owns several rail transport companies within Turkey as well as a 50% share of the İzmir-area commuter rail system, İZBAN.