<human>: Hi, 

I am planning to visit Turkey and Iran in April 2015. The plan is to fly in to Istanbul (4 days)-> Ephesus (1 day) -> Denizli ( day trip) -> Konya ( 1 day) -> Cappadocia (3/4 days) -> Ankara (transit) and then catch the trans asya ekspresi straight to Tehran. The primary motivation for me is to experience a long distance train journey and escape the city life for a day or two.

After arriving in Tehran, I will go visit a few cities and then return to Tehran and fly back. Since I am located in Dubai, flights (Dubai-Istanbul and Tehran-Dubai) are cheap and I have on Emirates so the airfare costs are pretty low. 

My question is: How do I buy the train ticket from outside Turkey for the Ankara-Tehran train? I need to buy this before applying for the Turkish tourist visa (I can not get an on-arrival visa in Turkey) to show that I am exiting the country somehow. A few online resources say that even travel agencies cannot buy the international Turkish train tickets for people outside Turkey. This essentially makes my application for the Turkish tourist visa incomplete.

The Iranian visa should be fairly straightforward for me since I am not American and my family members have visited several times alone.

Also please feel free to critique my Turkey itinerary

Can you provide a brief overview of the text?
<bot>: How do I get the Ankara-Tehran train tickets from outside Turkey because it is a vital part of my Turkish tourist visa application?