New Garia: A 9,400sq m mass transit hub is coming up next to Kavi Subhash station with two Metro lines one above the other, a parking bay and shopping complexes on either side. Once it is ready, New Garia will be a Metro interface for three routes, besides the suburban railway line.

The new building, which railway officials said would become operational by December 2020, is meant to be the terminal station for the New Garia-Airport link along with a provision for extension of the Metro lines till Baruipur. The building will be linked to the existing Kavi Subhash-Dum Dum route and Eastern Railway's suburban line.

Construction of the new station did not start for more than seven years after the project was commissioned in 2011 because of a land logjam. The proposed maintenance shed for rakes could not be built either.

The state government has now asked the railway authorities to go ahead with construction. "The civil engineering part will be completed by June 2019 and there is an internal deadline to make the station for the airport line operational by December 2020," a senior railway official said on Monday.

He said the existing maintenance shed for the Kavi Subhash-Dum Dum line will be used for rakes plying on the airport route.

A large portion of the basement level was completed on Sunday. A 4,000-cubic metre concrete slab was built in three days, officials said.

The new station will be 22 feet underground, the lowest level being a car park. The booking counters will also be at the basement.

Commuters would need to go down to the basement to buy tickets and come up to the station level, about 20 feet above, to catch a train to the airport. There will be four platforms, including "an island", for the airport line.

The existing underground stations have booking counters at the concourse level and passengers have to go down to catch a train. "The plan is to integrate the station with two other lines so that passengers can use a corridor to switch to the Dum Dum line or the suburban line," an official said.

About 16 feet above the platforms for the airport line, there will be a concourse with administrative offices. There will be a provision another 16 feet above for the proposed Baruipur extension. The railway ministry has done a feasibility study for that route but has yet to sanction it.