Rail operators are concerned that a multibillion-pound programme to buy much-needed new carriages could be delayed because two thirds of the country's train leasing industry is about to change hands.

Porterbrook, the train leasing company, has been sold by Abbey to Deutsche Bank for an estimated £2 billion and details of the deal will be announced this week. Meanwhile, HSBC has appointed NM Rothschild to conduct a strategic review of its eight-year-old HSBC Rail business, which could also lead to a sale.

This year, Angel Trains, which owns the distinctive Pendolino trains used on the West Coast Main Line, was sold by RBS to the Babcock & Brown European Infrastructure fund, an offshoot of the Australian investment company, for £3.6 billion. Deutsche Bank was one of the banks that backed the deal.

The Department for Transport is in the process of buying 1,300 carriages to improve capacity for commuters across the rail network.

New carriages are being bought for services that run through London between Bedford and the South Coast, while additional Pendolino carriages are being procured for use in 2012 on the Virgin-operated West Coast Main Line. The department is also about to shortlist potential manufacturers for between 45 and 55 new Intercity Express trains that will be brought into service between 2013 and 2018.

“There will be questions about the ability of the new owners to fund these huge procurement contracts, even though they are underwritten by the Government,” a rail insider said.

The UK's rolling stock business has been under scrutiny by the Competition Commission for the past two years, which has been one of the reasons that the banks were keen to sell their businesses.

However, the Competition Commission's provisional findings, released in August, did not blame the three main rolling stock leasing companies (Roscos) for making excessive profits, as expected, but criticised the way the Government lets rail franchises. The Commission found that train operators had a “very limited number of rolling stock options available” when bidding for franchises, restricting competition.

The DfT, which took back responsibility for train procurement several years ago, has also attracted industry criticism for micro-managing the procurement operation and for demanding that manufacturers' tenders cover a multitude of options for new trains.

While HSBC has appointed NM Rothschild to conduct a review of its profitable rail leasing arm, it is not thought to be committed to its sale, because of the difficulty of selling any asset at the moment. The bank is understood to be considering expanding the company into Europe where there is new demand for leased trains, as states proceed with rail privatisation.

Both Abbey and HSBC denied that the sale of their rail leasing businesses was necessary to raise fresh capital.

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