The Railways has identified four potential high speed corridors linking industrial centres which have the capacity to pay and existing air traffic that can shift to trains.

Among the proposed lines are Mumbai-Ahmedabad, Chennai-Bangalore, Bangalore-Hyderabad and Dhanbad-Howrah.

A feasibility study is being carried out on the Mumbai-Ahmedabad segment. The project, placed as a technology demonstration project, aims to introduce trains running at speeds of more than 250 kilometres per hour.

The faster passenger trains currently in operation run at speeds of around 110 kmph. The

Japanese government has expressed interest in assisting India on the project, estimated to cost Rs 8,500 (Rs 5 billion) crore.

Transportation experts, however, are sceptical of the feasibility of the project, which they say will not be able to beat airlines in terms of time taken to travel or on the cost of tickets. In fact, they say, the Mumbai-Ahmedabad Shatabdi has been withdrawn for the third month in succession because competition from Volvo buses has reduced train occupancy and made the line commercially non-viable.

Inter-city trains work well in a country like Germany, where the time taken to travel via a high-speed train is comparable to the time required to fly to the destination.

"Germany is not a very large country and flying involves additional time of travelling to the airport, checking in and checking out. On the whole, the total time required to fly and to travel by train are comparable," they said.

India, in contrast is a large country and flights would still be quicker than trains. For instance, it takes only one hour to fly from Mumbai to Ahmedabad and even with the high-speed train, the time required for travel would be two and a half hours.

Longer travel time and rail tickets, which would cost more than air tickets are not bound to be a hit with passengers, they added.

The Japanese are offering preferential official development assistance at very low rates of interest with a 40-year repayment period.

The package on offer, however requires the Indian Railways to procure at least 30 per cent of the equipment from Japan.

The offer was made by the Japanese foreign minister who met Prime Minister, Manmohan Singh in early August. Singh directed the Railways ministry to prepare a concept paper on the project, which he felt could be a technology demonstration project for the country, officials said.

Rail India Technical and Economic Services Ltd is conducting a feasibility study, which is expected to be completed by September this year.

The high-speed trains will run on dedicated high technology tracks which have no interface with road traffic. These tracks will be fully fenced to prevent animals from getting onto the tracks and causing accidents.