Tehran airport is now connected by subway line 8. This change has caused much controversy and resentment amongst cab drivers and minibuses, understandably though. Before the opening, you had to rely on private taxis which typically charged 25/30 for a ride to Tehran city. With metro line 8 taking you first to Shahed and transfer line 1 to City. The train ticket cost less than a dollar. Once you leave the airport, cross the bridge and follow the signs. There was a manned ticket counter. This paper pass let you open the small gate and you are in heading down the stairs to the platform.