Railtrack could end up paying out millions of pounds more in compensation following last year's disruption of the network, it emerged yesterday.

One of the train operators worst affected by the crisis, GNER, based in York, has won the right to sue for extra compensation.

Railway insiders are studying the situation closely to see whether or not other operators could claim extra cash from Railtrack, adding to the company's problems.

GNER runs the East Coast main line Intercity services, linking London and Scotland through York, Darlington and Newcastle.

The operator has successfully claimed that there was a fundamental change to the network when Railtrack had to impose major speed restrictions last year, in the wake of the Hatfield crash in October 2000, which killed four people and left 34 injured.

The latest decision, by the industry's independent Network Change Committee, means that GNER can claim compensation for long-term damage to business, not just loss of revenue.

And although all other operators have had final settlements from Railtrack, some of the franchise holders are now said to be looking at ways of reopening talks.

GNER and Railtrack have begun mediation on the final sum, with GNER claiming more than £100m in total. It is understood the two sides are close to an agreement.

A spokesman for GNER said yesterday: "It is no secret that we have put in a claim and are waiting to hear the outcome. Until then we regard this as sub-judice."

A spokesman for Railtrack said: "We hope to come to an amicable conclusion as soon as possible and hope to put this chapter behind us once and for all."

Railtrack has put aside £100m for compensation to operators, above its direct performance penalties.