NEW DELHI: The IGI airport will soon get its own "air train", a dedicated Metro, for passengers to transit from one terminal to another. Leading airports of the world like New York's JFK, London Heathrow, Hong Kong and Zurich have long had free-to-use Metro lines between their terminals and Delhi will be the first Indian airport to boast of the same.

"Delhi International Airport Pvt Ltd (DIAL) has proposed an automated people mover (APM) between terminal 1 (low cost domestic), T2 (old international which will make way for a new T4 in 2020) and T3. Work on it was originally supposed to begin in 2020 alongside the construction of T4, but, given the growth at Delhi airport and volume of traffic, the aviation ministry has told us that the APM should be expedited and made ready at the earliest," said a highly placed source.

At present, passengers transit between terminals by buses. Till the tunnel road was ready, buses used to go via NH-8 in front of Radisson — something that could take upto 45 minutes. The tunnel route has cut commute time to half an hour.

DIAL is going to ask Delhi Metro Rail Corporation (DMRC) to do a technical study on the routing and also give an indicative costing of the air train project. The airport operator has held initial consultations with a New York-based firm.

Based on that, the plan is to have four stations for its air train — at T1, Aerocity (the hospitality district), cargo terminal and a common one for T3 and T2/4."By our estimates, the line should be 5.5-km-long with 3km underground section and 2.5km on ground. The average costing of each kilometre of under and on ground Metro line is up to Rs 500 crore and Rs 200 crore. It should cost Rs 1,500-2,000 crore. All this will be known for sure once DMRC gives its report to DIAL," said the source.

With this, the annual capacity at T1 will rise to 3.5 crore while T3-T2 will collectively handle about 4 crore passengers by 2020. Clearly there will be a large number of passengers transiting between T3/2 and T1 for flight transfers. The next phase in 2025 when T4 is ready, will see an annual traffic rise to 9.2 crore. The eventual capacity of IGI airport is about 10 to 11 crore passengers per annum. Once T4 is ready by 2025, T3 which is integrated domestic-cum-international could be made all international and T1, T4 could be all domestic.