The group, which runs most of Britain’s overground track, signalling and larger stations, is expected to make its final pitch in a five-yearly pricing review tomorrow.

In June, the Office of the Rail Regulator, which sets Network Rail’s earnings, said the company should receive £26.5 billion over the five years from next April. This was £2.5 billion less than it had asked for.

Tomorrow, it is expected to say it needs only £1 billion more than offered, but won’t be able to make a further £1 billion demanded in cost cuts.

“We can meet the regulator’s efficiency targets, but not in the time frame he wants,” said one source close to the company. The group is expected to present a raft of consultants’ reports to back up its spending demands.

It is also confident of meeting a deadline for a large increase in capacity on the West Coast Main Line. The new timetable, made possible by extensive engineering work on the line, is likely to be phased in from December 14.

Trains will run from London to Birmingham and Manchester every 20 minutes, rather than every half-hour.