It’s possible to travel with high speed trains with speed upto 250 km/h, long distance trains departing from metropols and regional trains between neighbour cities in Turkey.
There are a couple of international trains between Turkey and other countries. There are international train services to Bulgaria, Austria (not during winter), Romania (during summer) and Iran.
International train tickets are on sale 60 days prior to departure, and only can be bought from international ticket offices. Online ticket is not possible.
High speed trains
High speed trains are generally moving on private lines with speed up to 250 km/h. There are services between metropols like Istanbul, Ankara, Konya, Eskisehir. New lines are under construction and more are planned.
High speed trains are generally punctual. In some lines, there are over 10 departures in each direction. Tickets are on sale 15 days prior to departure. Online ticket is possible. Tickets are sold out very quickly.
Main line (long distance) trains
Long distances trains are less day by day similar to trends all over the world.
Main line trains are connecting metropols like Ankara, Izmir, Adana to far away destinations. With a few exceptions, they depart once a day.
All long distance trains have pulman wagons. If overnight, there are couchettes and/or sleepers as well.
Pulman wagon seats are 2+1 (double + solo seat in one row), reclining and comfortable, distance between two seats is quite enough. Double seats are sold gender specific unless they’re sold together.
Couchettes have 4 seats. During night, 4 beds replace seats. Pillow and blanket is given for night. Compartments are gender specific, unless reserved together.
Sleepers have two beds, washbasin, air conditioner and electric socket. If one passenger reserves the compartment, the other is not for sale, thus surcharge is applied for single tickets.
Main line tickets are for sale 30 days prior to departure. Online ticket is available. Sleepers and couchettes in overnight trains are very popular and sold out very quickly.
Trains running between neighbour cities are the main transport modal in some routes such as Adana-Mersin trains, which depart 20+ times per day in each direction.
With a few exceptions, regional train tickets can be bought only at stations on route. No seat reservation. Some are very crowded and you may not be able to find a seat and travel on foot.
Some wagons of some regional trains are sold at internet. These tickets come with a seat reservation.