The so-called operator of last resort is finding it hard to cope with a mounting workload caused by the implosion of train companies

The government’s in-house train operator faces a struggle to recruit enough rail experts as concerns mount that at least five major franchises are at risk.

Sources said that the so-called operator of last resort (OLR) — a subsidiary of the Department for Transport — was finding it difficult to cope with a mounting workload caused by the implosion of train companies.

A number of former railway executives are understood to have been asked to come out of retirement to work for the organisation amid uncertainty over the future of the franchising system.

Grant Shapps, the transport secretary, has raised the possibility of renationalising Northern Rail within the next three weeks because it is close to financial collapse. He has asked the OLR to draw