Chennai, Feb 14 (ANI): Prime Minister Narendra Modi inaugurated the Chennai Metro Rail Phase-I extension on February 14. The total project cost Rs 3770 crores. This 9.05 km long extension will link North Chennai with the Airport and Central Railway Station. PM Modi also inaugurated the fourth Railway line between Chennai Beach and Attipattu. This 22.1 km section, laid at a cost of Rs 293.40 crores, traverses through Chennai and Thiruvallur Districts. PM Modi lays the foundation stone for the Discovery Campus of IIT Madras. The Campus will be built at Thaiyur near Chennai at an estimated cost of Rs 1000 crores in the first phase, over an area of 2 lakh sqm.