The Conservatives are backing detailed studies into three major potential rail projects, including the Maglev 'levitating' train and a high-speed north-south rail line.
Shadow transport secretary Chris Grayling said that although he accepted the need for short-term projects, such as cutting congestion on certain roads, Britain's long-term transport needs may require some new major infrastructure projects.
The party has commissioned feasibility work into three schemes, the first of which would be the construction of a French TGV-style high-speed rail network running from London to Scotland, carrying trains travelling at about 180 miles per hour.
Another option could be the MagLev trains, where carriages float on a magnetic field above the tracks and are propelled by changing the field's charge. In August, shadow chancellor George Osborne went to Japan to see the results of a three-year trial there.
A third study will also look into the development of a new dedicated freight route, possibly using derelict or under-used existing rail corridors, to link ports, the Channel Tunnel and Britain's major business centres.
A recent government-commissioned report on Britain's future transport needs was unenthusiastic about the benefits of high-speed rail links, and said the government would be better to invest in small-scale improvements.
Rod Eddington's year-long study concluded: "New high-speed rail networks in the UK would not significantly change the level of economic connectivity between most parts of the UK, given existing aviation and rail links."
The report acknowledged that such networks could ease congestion between cities and in London, with "real and substantial" benefits, but warned: "Crucially though, these goals could be achieved by other solutions, and perhaps at much lower cost."
Today Mr Grayling said the Tories supported quick-fix measures to deal with Britain's congestion problems, including putting in longer trains, improving bottlenecks on individual roads and making improvements to transport interchanges.
However, he warned: "Beyond that we will need to bring forward longer term projects to tackle the capacity constraints that are hindering both economic development and the kind of modal shift that will be needed to help our battle against global warming."
He said: "Any of the three options we are looking at would be expensive, and would probably need to be developed in phases in the way our motorway network was.
"But we would not be doing our job properly if we were not looking at the longer term as well as short-term challenges."