Tehran's Metro system is planned to consist of a total of seven lines; 7 lines (Lines 1–7), six of which are metro-service lines (Lines 1–4 and 6 & 7), are currently operational. Lines 1 and 2 cross each other at Imam Khomeini station. Line 5 is a suburban rail line that attaches to the Line 2 at the Tehran (Sadeghieh) station; it extends into the Karaj area and is connected to the rail line of city of Karaj & line Imam Khomeini Airport is a metro express.