A NEW high-speed railway line could be whizzing through Swindon as part of the largest track build since the 19th century.

Network Rail will announce today that it is commissioning a feasibility study to assess the need for high speed trains, similar to the French TGV or Japan's Shinkansen "bullet trains", to cope with the country's growing number of rail users.

One of the proposed lines would run alongside First Great Western's London to Bristol route and that could see trains transporting Swindon rail users at speeds of 100mph.

It comes at a time when passenger numbers have increased by about 40 per cent in the last 10 years.

More people are using the service than at any time since 1946.

Numbers are expected to increase by a further 30 per cent in the next 10 years, adding to the burden on the current network.

The study being commissioned by Network Rail will look at the service in the post-2014 period, with all options on the table.

As well as the London to Bristol line, the West Coast line to Birmingham, Manchester and Glasgow, the East Coast line to Edinburgh, the Midland main line to Sheffield and the Chiltern route to Birmingham will also come under consideration for a new high-speed service.

The London to Penzance line will also be looked at as part of the review.

If the proposals are adopted, the new tracks are likely to be built with high-speed passenger trains in mind.

A spokesman for Network Rail said: "We are looking at these five strategic routes. We are possibly looking at new lines.

"There is a huge case to be made for an expansion of the rail network.

"All options are on the table looking at how we address capacity issues."

Earlier this year Swindon commuters joined fellow train users in a fare strike on First Great Western services.

The Swindon-based train company came under renewed fire from passengers for soaring fares and unreliable services.

Members of the More Train Less Strain campaign group were so fed up they wore cattle masks as they boarded their trains yesterday morning in protest at being herded into carriages like animals.

Ashwin Kumar, the passenger director of independent watchdog for rail users Passenger Focus, said: "We welcome the study. It is important the rail industry anticipates future growth."

And Richard Dyer, the transport campaigner at Friends Of The Earth, also said the review was needed.

"Expanding Britain's railways by building new high speed lines is potentially very exciting and could play an important role in weaning Britain off fossil fuels and developing a low carbon economy," he said.

"But the overall impact that this would have on local people and the environment must be carefully considered.

"The UK needs a modern, comprehensive and affordable rail network to provide a real alternative to cars, lorries and short haul flights, and help cut Britain's contribution to climate change."