If you gonna travel within Turkey, most probably you’ll focus on one or both of the two solutions. Either a very fast one by plane, or by bus which can take you almost to anywhere in Turkey.
However, millions of people in Turkey had preferred a third one. In 2012, almost 20 million of people traveled by train in Turkey. That number was 26 million in 2011, some of which had been lost due to closures (all trains departing from Istanbul was the biggest lost).
Although the share is 2% among all domestic modes, the big investment in high speed lines may increase this figure in near future.
On the other hand, even the current lines is ready to take you to anywhere in Turkey with railway connection. Some are really slow, and some can be accepted as “shabby”. But all are ready to offer you a travel fun. You will enjoy the view otherwise impossible to see, can sit in wide seats without looking for an emergency exit, even can sleep on bed in some, eat at a restaurant in some others, and talk for hours with your friends face to face.
Here is the passenger train guide of Turkey for the ones that has not discovered yet:
Map: Onur Uysal