along with two other routes of the Diamond Quadrilateral project. A senior Railway Ministry official told PTI.
Bullet train is expected to run about 300 km per hour on the dedicated track.
The corridor is estimated to cost about Rs 84,000 crore.
Diamond Quadrilateral, one of the ambitious programmes of the NDA government, will connect four metro cities through high speed rail network.
The report by the Spanish firm said that the travel time between Delhi and Kolkata on the proposed bullet train will take 4 hours 56 minutes as against the 17 hours in Rajdhani.
There are about 12 cities including Agra, Lucknow, Varanasi and Patna between Delhi-Kolkata high speed route. The report says the travel time for Lucknow, Varanasi and Patna will also decrease significantly once the high speed corridor is commissioned.
While the travel time for Lucknow is likely to be 1 hour 45 minutes, one will reach Varanasi in 2 hours 45 minutes from the national capital.
However, there is no separate study for Delhi-Varanasi or Delhi-Lucknow route and the study is for the whole Delhi-Kolkata route. The final report will be submitted by the year end.
Feasibility study is also being carried out for Delhi-Mumbai and Mumbai-Chennai high speed corridors of the Diamond Quadrilateral project. The study for the Chennai and Kolkata route is yet to be taken up. The Indian Railways is going ahead with the Mumbai-Ahmedabad corridor with the Japanese help.