NEW DELHI: Travelling time between Delhi and Kolkata will be cut down to as less as five hours by operating a bullet train on the route, a firm commissioned by the Railways has suggested.The feasibility study is being undertaken for the 1,513 km long Delhi-Kolkata high speed corridor along with two other routes of the Diamond Quadrilateral project, said a senior Railway Ministry official.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.According to the feasibility report by the Spanish firm, 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, he said.Bullet train is expected to run about 300 km per hour on the dedicated track.There are about 12 cities including Agra, Lucknow Varanasi and Patna between Delhi-Kolkata high speed route.As per the report, 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.The official, however, said 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.Meanwhile, the Railways is going ahead with the Mumbai-Ahmedabad corridor with the Japanese help.