Sir Richard Branson's stranglehold on the rail route from London to Glasgow could be weakened by one of two rival train companies that are understood to be bidding against Virgin Trains for a key contract.

The project management contract to oversee the introduction of new train carriages, which has been put out for tender by the Department for Transport (DfT), has attracted the interest of Govia, a joint venture between Keolis and Go-Ahead, and Serco Rail.

Securing the job could give the rival train operators inside information on the West Coast franchise, which in turn could help them eventually to beat Virgin when the franchise comes up for grabs in 2012.

By then, the London-to-Glasgow franchise is expected to be one of the most lucrative in Britain, with 33 per cent more seats on each train than at present.

The project manager will oversee the introduction of two new carriages to 35 of Virgin's 52 trains. The new carriages are necessary to head off the threat of overcrowding on the West Coast Main Line.

Whoever wins the contract will be at the centre of improvements to the London-to-Glasgow route over the next three years and will have the difficult task of liaising between Alstom, Virgin Trains, Network Rail and the DfT, which has responsibility for train purchasing.

The project manager will be paid on a cost-plus basis and will oversee the extensive testing that is needed to introduce the new carriages and possibly the improvements to stations, including lengthening platforms, that will be required.

Virgin Trains had proposed that it should oversee the addition of extra carriages in return for a two-year extension of its franchise. Ministers rejected the request out-of-hand.

The project management role appears to be a compromise to handle the tricky project of introducing new trains, so that the department does not have to give in to Virgin's request for a franchise extension.

The first step in the extension of the Pendolino trains will be taken this week when the DfT is expected to award the rolling stock contract, potentially worth about £500 million, to Alstom Transport, The Times has learnt.

Alstom will supply four new complete trains and seventy new cars.

The company built the original Pendolino, which came into service in 2004, and maintains the trains on the West Coast.

There has been criticism of the DfT's handling of new train orders recently from train manufacturers and train operating companies, who say that the process has become much more complicated since it was taken over by the DfT.

This month it emerged that a consortium of Alstom Transport and Barclays Private Equity that had been bidding for a contract for new Intercity Express trains worth billions of pounds had pulled out because of the complexity of the requirements.

The two remaining bidding consortiums have asked for a postponement of the bidding deadline because they were having difficulty making sense of the requirements.

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