The Chennai Mass Rapid Transit System, a state-owned subsidiary of Indian Railways, is a metropolitan elevated railway line operated by Southern Railways. It is the first elevated railway line in India. Although it is segregated from the Chennai Suburban Railway, they both are operated by Southern Railway and are integrated in a wider urban rail network. Built at a cost of ₹ 11,710 million, the line runs within the city limits from Chennai Beach to Velachery, covering a distance of 19.34 km (12.02 mi) with 18 stations, with an average daily ridership of 100,000 commuters a day. Connecting the central business area of old Madras with the IT corridor, the section has a potential capacity of 425,000 passengers a day. In 2011–2012, MRTS registered a revenue of ₹ 198.9 million, registering a 16.25 percent increase, with 134 trains plying across all the 17 stations.[5]

The MRTS is proposed to be taken over by the Chennai Metro Rail Limited thereby bringing all the elevated tracks and underground tracks inside the city under one organisation.Upon completion of the takeover, all current MRTS trains would become air conditioned and consequently, the fares would be raised to match that of the Chennai Metro. The takeover is expected to be completed by the year 2021.