An extra 1,000 train carriages will be provided to combat overcrowding on Britain's railway network, the government is expected to announce.
The transport secretary, Douglas Alexander, will unveil plans for the introduction of the new carriages later today, sources close to the Department of Transport are said to have indicated.
According to reports, the new stock will be used to lengthen existing trains on the most crowded parts of the rail network, with a number of the carriages likely to be used to ease overcrowding on services in London and the south-east, where passenger congestion is at its greatest.
It is understood that the additional rolling stock will represent around one-tenth of the current rail fleet, with the government set to pay for the newly-built carriages, which will subsequently be leased to train operators at a cost of around £130 million a year.
Ministers are said to want the new stock to be ready for use by 2014.
News of the expected announcement comes amid growing passenger numbers on Britain's railways, with ten per cent more people using the rail network last year amid rising congestion on the country's roads.
Meanwhile, official statistics show that total passenger kilometres travelled on the rail network increased from 32.5 billion in 1991/02 to 43.2 in 2005/06.
Last week the Department for Transport launched a procurement process for the commission of a new generation of intercity trains, in what was described as the UK's "most significant" investment in rolling stock for over 30 years.