Tehran Metro is a rapid transit system serving Tehran, the capital of Iran. It is the largest metro system in the Middle East. The system is owned and operated by Tehran Urban and Suburban Railway. It consists of six operational metro lines, with construction under way on seven lines including northwestern extension of line 4, southeastern extension line 6, northwestern and east extension line 7, east extension line 2 and Line 10, Line 8, Line 9 and 11.