There's no train station inside the terminal. To travel by train to Chennai you need to walk to the freeway and take the tunnel to Tirisulum train station. Buy a first-class ticket, because the rest of the train is often crowded. A subway station is expected to be opened in 2014, allowing travelers to travel directly by subway from the terminal to Chennai.
Car and bus
Chennai International Airport is situated 19 kilometers southwest of the city center. The airport is easily accessible by rental car, at least outside rush hour, via the National Highway 45. The exit to the airport is clearly signposted.
Bus 18A connects the terminal with Chennai's center. Allow approximately 45 minutes traveling time. There's also another bus with almost the same number, B18, which is slightly more expensive, as it's air-conditioned.
Car rental Chennai Airport
You can rent cars in the Arrivals Hall. There are three car rental companies present at Chennai Airport: Avis, Budget and Hertz. They rent out cars with and without a chauffeur. The minimum age to drive a rental car yourself is 25.
When leaving the terminal, you will be stormed by taxi drivers wanting you as a client. To avoid this chaos you better book a taxi at one of the many ticket kiosks. You will then be guided to the taxi of the respective company and won't be bothered by obtrusive people. A taxi ride from the airport to Chennai's center will cost about 450 rupees.
There are parking lots in front of both terminals offering space to 600 (domestic terminal) and 1000 (international terminal) cars. The rate varies between 60 and 100 rupees.