But terminating the service at Dasnagar, may spell doom for Howrah station that is virtually bursting at its seams. A KMDA study has found that the passenger dispersal system at Howrah is inadequate and traffic has far exceeded the saturation level. If the Metro is terminated at Dasnagar, there would be total chaos at Howrah, said a transport expert.

The use of powerful tunnel boring machines would ensure that the construction of the metro corridor 70% of which is underground would not disrupt traffic overground. "The tunnel from New Dasnagar to Eastern Metropolitan Bypass that will pass below the Hooghly would be an engineering marvel," said a senior transport department engineer. The elevated portion of the Metro would be in Salt lake.

A Japanese team that closely studied the North-South Metro has also suggested a technological shift to make the new Metro a more efficient mass rapid transit system. "The team has suggested linear metro that would operate on the standard gauge rail and runs faster. The train can easily climb up a steep slope. However, the choice of technology would finally be made by the high-powered committee of the state," said a senior officer of transport department.

The Japanese team is feeding all existing data into a format. "The report would be placed before the Japanese parliament for the nod. JBIC is keen to fund the project," said a member of Japan's project funding approval committee.