Hundreds of train carriages are lying idle in sidings, despite chronic levels of overcrowding, because rail companies cannot agree on who should use them.

Most of the carriages could be brought back into service immediately, adding 10,000 seats.

Douglas Alexander, the Transport Secretary, said on Wednesday that 1,000 extra carriages would be bought by 2014 and claimed that the Government was acting as quickly as possible to address overcrowding, which results in more than 100,000 passengers a day having to stand for up to an hour in the morning peak.

The Times has learnt that a fleet of the most reliable, comfortable trains has been sitting unused in sidings at Eastleigh, Hampshire, for the past two months. A second fleet of trains, built only six years ago, is to be removed from service on the Great Western line because train companies are unwilling to pay for them.

Another 150 carriages are mothballed at Long Marston, a former Ministry of Defence depot in Warwickshire.

The Department for Transport (DfT) says that it is powerless to intervene but passenger groups argue that the problem is the absence of a strategy for making best use of trains. Before privatisation, British Rail was able to shuffle trains about the country to suit needs.

Britain’s 10,000 carriages are owned by three banks and leased to train companies. The companies are trying to save money by hiring as few as possible. The 120 Class 442 carriages at Eastleigh were only halfway through their 30-year service life when South West Trains retired them in January.

London TravelWatch, the passenger watchdog, said the 442s should be sent to Southern, which operates from Victoria and London Bridge. Southern in turn could release 50 Class 319 carriages to First Capital Connect, which operates the severely overcrowded Thameslink route across London.

First Capital Connect has so few trains that some of its peak services have four carriages instead of the usual eight.

The 319s are the only trains it can use because they are capable of running on the different voltages either side of the Thames. Southern is refusing to agree to the swap, claiming that the 442s take seconds longer to unload passengers because they have fewer doors.

Chris Grayling, the Shadow Transport Secretary, said: “It is absurd that, at a time when trains are so overcrowded, ministers and the train companies cannot find a way of making use of these spare carriages.”

Southern said that overcrowding on First Capital Connect was not its problem but added: “We are in discussions with the DfT over this.”

A DfT spokeswoman said: “We want to secure extra coaches for the Thameslink route and we are working hard with the rail industry to deliver this. We are actively considering a number of options.”

Bombardier, which owns Britain’s last train factory, said that it could start delivering new trains within 18 months.

Explore UK News

• Crime News

• Education News

• Health News

• Scotland News

Times Recommends

• He stole my son, now I’m alone in hell
• Back on the air, but don’t mention Mugabe
• Ten kitchen gadget gift ideas