I plan to take a train to Tehran(Iran) from Van next year, but I heard some information that, as from August 2015, the Trans-Asia Express is temporarily cancelled until further notice, after security incidents in Eastern Turkey. Is this information correct? Will the train running next year?(June,2016) If this route is closed, how can I go to Tehran(Iran) from Van?
Yes, it’s temporarily suspended due to security reasons. Please check or ask it again on the time of travel.
You can follow up-to-date details at Transasia Express.
Another option would be taking bus from Van to Tabriz and continue with train. You can buy online tickets at iranrail.net.