The Tehran Metro is referred to a fast transportation system serving Tehran. By November 2017, This system consists of 7 subway lines (and an extra suburban train line), with five lines (7-2-1-3-4) in the city and two other outskirts (between Karaj and Tehran). The length of the operational metro lines, is 221 km with 118 stations, and the number of active carriages in Tehran Metro is more than 1,000 wagons, in the mean, carrying more than 3 million passengers per day. Tehran Metro has achieved a record of 4 million passengers a day.
Although the prototype of Tehran Metro was introduced during the reign of Mohammad Reza Shah Pahlavi, it officially began to work in 1999. The first active route was the No. 5 Metro route, which moved between Tehran and Karaj and began its activities on March 7, 1998.