# Yüksek Hızlı Tren

Yüksek Hızlı Tren or YHT (English: High Speed Train) is a high-speed rail service operated by TCDD Transport in Turkey. Branded as "YHT", they are TCDD Transport's flagship passenger train service and the only high-speed rail service in the country. As of 2025, the network spans 1,385 km (860.6 mi) and serves major cities like Istanbul, Ankara, Eskişehir, İzmit, Konya, and Sivas. Expansion of the system is underway and the network is expected to reach Edirne, Afyonkarahisar, Adana, and İzmir in the 2020s.
High-speed rail in Turkey was originally planned to be built as early as 1975, but it wasn't until 2003 that the construction of the Ankara-Istanbul high-speed railway began. The first section was completed in 2007, between Eskişehir and Esenkent with passenger operations beginning on 13 March 2009 between Eskişehir and Ankara. On 23 August 2011, the Turkish State Railways inaugurated its second high-speed railway to Konya and on 25 July 2014, the railway was opened to Istanbul. The State Railways have integrated the YHT network with other projects done in major urban areas. In Ankara, the route was expanded from three tracks to five tracks to allow for frequent Başkentray commuter rail service, along with a new high-speed rail concourse at Ankara station. In Istanbul, YHT trains use the Marmaray Tunnel to traverse the Bosphorus Strait and reach the European side of the city.
YHT trains run on both dedicated high-speed railways, as well as existing conventional railways that have been upgraded to allow speeds of 200 km/h (124 mph) and 160 km/h (99 mph) respectively. The latest expansion of the network happened on 26 April 2023, with a 406 km (252 mi) expansion from Ankara to Sivas, along the newly built Ankara-Sivas high-speed railway.

## History

Istanbul and Ankara are Turkey's largest two cities, having a combined population over 20 million. Transportation demand between the two cities is expectedly high. The Otoyol 4 motorway is a major highway between the two cities, and the Ankara–Istanbul route is the busiest domestic air route in the country. The route between Istanbul and Ankara by rail has been a single-track line, and trains usually were delayed 30 minutes to 2 hours plus the average 7 hours, 30 minutes travel time. Rail transport in Turkey was already at its lowest point, so in 2003 the State Railways and the Turkish Ministry of Transport made an agreement to build a 533 km (331 mi) line between the two cities. The line would be an electrified double trackline. Construction began in 2004 from Esenkent to Eskişehir. The line was completed on 23 April 2007.
On 28 February 2007 TCDD requested bids for high-speed train sets from other networks to be tested on the completed portion of the high-speed line.
On 30 March 2007, TCDD signed an agreement with Trenitalia of Ferrovie dello Stato to rent an ETR 500 train set for 4 months for testing the system.
The first run was from Haydarpaşa Terminal in Istanbul to the Central Station in Ankara, using the completed portion of the high-speed line between Hasanbey and Esenkent.
On 14 September 2007 the ETR 500 Y2 set a speed record in Turkey, reaching 303 km/h (188.3 mph). This test received extensive media coverage in Turkey.
On 20 November 2007 the first TCDD HT65000 high-speed train sets purchased from CAF of Spain entered Turkey from the Kapıkule border station in Edirne, and tests were subsequently made with these trains prior to the commencement of services on 13 March 2009.
In 2010 one of the YHT trains was converted into a test train in order to test and measure the new lines. The Transportation Ministry spent 14 million TL (around 7 million Euros at that time) for the installation of testing and measuring equipment on the train, which it named – because it is a tradition to give a name to test trains – as "Piri Reis" after the renowned Turkish admiral and cartographer who drew some of the most accurate and detailed maps of the Mediterranean Sea and the Americas in the early 16th century.
TCDD requested bids for the name of the high-speed service. Out of over 100 entries, the ones with the highest votes were: Türk Yıldızı (Turkish Star), Turkuaz (Turquoise), Yüksek Hızlı Tren (High Speed Train), Çelik Kanat (Steel Wing) and Yıldırım (Lightning). TCDD chose Yüksek Hızlı Tren to be the name of the service.
On 13 March 2009, the inauguration ceremony took place in Ankara; attended by President Abdullah Gül, Prime Minister Recep Tayyip Erdoğan, and Minister of Transport Binali Yıldırım, who started the first phase of the YHT service running between Ankara and Eskişehir.

## Ridership

Until 2015, ridership had grown at the expense of TCDD's regular train services and has not dented air traffic demand. Total TCDD services including HSR remain flat. Traffic was affected since 2012 when all services to Istanbul were suspended. A sharp increase in ridership occurred after extra high speed trains started operation. A further increase in 2018 and 2019 is expected with new trainsets becoming operational and the opening of the Istanbul terminals Halkali and Haydarpaşa.

## Lines in operation

As of 2024, there are four lines in operation: Ankara-Istanbul, Polatlı-Konya, Konya-Karaman, and Ankara-Sivas.

## Lines under construction and planning phase

Turkey's high-speed rail network is expanding, with three more high-speed railways under construction and several more planned. The Turkish State Railways plans to increase its network of high-speed rail to 3,500 km (2,200 mi) by 2023.

## Related infrastructure projects

The Marmaray project, which consists of a rail transport network around Istanbul and the world's deepest immersed tube railway tunnel under the Bosphorus strait, is also under construction. The Marmaray tunnel will connect the railway lines on the European and Asian parts of Istanbul and Turkey. In 2013 the Marmaray tunnel was opened and passenger transportation is started partially in 13.5 km of total 76.5 km. The rest was expected to be completed by 2015, but it now looks like this will not happen until some time in 2016. The project connecting the European and Asian suburban railway lines, will also connect the Thracian and Anatolian high-speed railway lines in Turkey via the world's deepest immersed-tube railway tunnel under the Bosporus.
A new high-speed rail terminus station is to be built in Ankara (2009–2010), which is to be funded as a public–private partnership, using the Build-Operate-Transfer model. Additionally, new stations are to be constructed in İstanbul, Izmir, Edirne, Trabzon, Erzurum, Erzincan, Sivas, Kayseri, Antalya, Afyon, and Polatlı. Furthermore, an additional project called Başkentray is also underway which consist of the renewal of railways in the urban section of Ankara.

## Service and operation
### Speed limitations

The YHT operates at a maximum speed of 300 km/h (186 mph) on high-speed tracks. But the YHT also runs on non-high-speed and renewed tracks like the Köseköy-Gebze section of the Ankara–Istanbul high-speed railway where its top speed is 160 km/h (99 mph). Naturally, some speed restrictions also apply in urban sections while accessing the central station, especially in Ankara and Istanbul thus increasing journey times. The speed on these sections is expected to increase once renewal projects in urban areas (like Başkentray and second phase of Marmaray) are completed.

### Staff, operation and security

On YHT service, there is usually one train engineer (two on some trains), a train manager (absent in some trips), two train attendants and a café car attendant. Business-class passengers are served meals at their seats if they applied for while buying their tickets. When accessing the trains, passengers must pass a security check like in airports. Maintenance of the sets is done at the Eryaman Yard in Ankara.

## Trains

Currently, there are several series of high-speed trains that run the YHT service:
* TCDD HT65000, manufactured by CAF.
* TCDD HT80000, manufactured by Siemens, marketed globally under the brand Siemens Velaro. Turkey also signed contract for ten more Velaro trains. With this contract, the Turkish Velaro fleet will grow to 17 trains.
Every set has railroad cars with cabins in the front and rear car, cars for economy class passengers and car(s) for first class passengers. Additionally, some HT80000 sets have business class cabins with 4 seats. The seating arrangements are 3 seats in a row (1 on one side, 2 on the other side) in first class and 4 seats in a row (2 on each side) in economy class. Automatic sliding doors provide passage between cars. Baggage may be stowed in the overhead compartments above the seats, or underneath the seats. Wi-Fi service is available with power inputs for laptops in first and business classes and all sets are wheelchair-accessible (with places in economy class only). In economy class, seats are fabric-coated and have audio connectors and foldable tables. In first class, there are leather-coated seats and a visual and audio broadcasting system that can broadcast at least 4 hours on 4 different channels.