Although sleeper trains become less and less popular as daily life speeds up with planes and high speed trains, they are still the first choice of travellers who are looking for comfort and adventure.
Sleeper train services are now rare in Turkey, especially after departures from Istanbul stopped. On the other hand, all new international services recently started has sleeping options.
Here are the most beautiful trains that you can get in from Turkey and travel while sleeping:
# 9 – Ankara – Kurtalan train (Guney Kurtalan Express)
Guney Kurtalan Express is an overnight train running between Ankara and Kurtalan. The train had given name to famous Turkish rock band in 70s
There are sleepers (2 beds) and couchettes (4 seats/beds) in Ankara-Kurtalan train and also restaurant car.
Train departs everyday except Tuesday and Sunday from Ankara. The route is 1200 km long. Travel time is about one day.
Train passes through Kirikkale, Kayseri, Sivas, Malatya, Diyarbakir and Batman.
Kurtalan is not a touristic town and has very limited accommodation and transport options.
There are tours to Diyarbakir-Mardin using Guney Kurtalan Express.
Kurtalan Express (Ankara-Kurtalan) timetable, options and ticketing
Categories: Passenger
Rail Turkey En 
Excellent post. I love sleeper train travel and in the past often made the journey between Aleppo and Istanbul
wish we could do it soon
I would also suggest the routes serving Adana from Ankara and the (former? I hope it runs again!) one from Haydarpasa too: the section down from Ülükisla to Yenice especially is stupendous!
There’s only Toros Express on that route by now, between Adana and Kayseri.