The Union finance ministry has given permission to build tracks along the mint in Taratala for the Joka-BBD Bag Metro.

But the defence ministry is yet to allow the construction of a station on its land in Mominpur, which remains the last big hurdle for the project.

"We have received the no-objection certificate from the finance ministry and are now waiting for a clearance for physical handover of the mint land," a railway official said on Wednesday.

A portion of the mint's wall needs to be pushed back for the Joka-BBD Bag viaduct for which the railways would need 3,100sq m, an official said.

Rail Vikas Nigam Ltd (RVNL), the implementing agency of the project, has written to the finance ministry, seeking permission for the physical possession of the land so work can start.

"RVNL will have to build a new boundary wall and then demolish a portion of the existing one," the official said.

But another hurdle still remains in the project that has been riddled with land-related problems.

The railways had sought 2,500sq m land adjacent to the army's Command Hospital to build the Mominpur station. But the army has raised objections. A source said the army's Bengal headquarters has sent its report to the defence ministry, which will take the final call on the matter.

State chief secretary Sanjay Mitra has written to defence secretary G. Mohan Kumar requesting for "appropriate instructions" for fast issuance of an NoC for the Mominpur-BBD Bag stretch.

Following the army's objections, the state government has, however, proposed that the railways build the stretch without Mominpur station, the source said.

If the Mominpur station were to be omitted from the plan, 1,800sq m of land would be needed to build a ramp from where the tracks would go underground.

"But we are insisting on the station. Not having a station between Majerhat and Kidderpore, almost 2.5km apart, would defeat the purpose of a mass transit system like the Metro," another railway official said.

The thumb rule for Metro routes is to have stations 1.5km apart. The existing north-south Metro has stations within a kilometre of each other.

"The railway ministry will approach the defence ministry too," another official said.

The army has, however, agreed to allow a tunnel under the Maidan.

After Prime Minister Narendra Modi's recent videoconference, the defence ministry agreed to end a four-year stalemate and allow the construction of tracks for the Joka-BBD Bag Metro under the Maidan.

Railway minister Suresh Prabhu is scheduled to meet chief minister Mamata Banerjee on Thursday during his visit to Calcutta. He is likely to raise the issue of land-locked Metro projects.

A state government official said the process to shift several buildings from the Metro route had already started. "Now it's the turn of the Centre to resolve the land issue," he said.

Mamata Banerjee had announced the 16.72km Joka-BBD Bag Metro when she was the railway minister in 2010-11.

Work started in July 2011 but it ran into a host of problems, mostly related to objections from various quarters, including the army.