RAILTRACK is believed to have abandoned hope of a negotiated settlement in the signal workers' dispute and changed tactics to imposing individual contracts.

The company is to test its new methods on Monday at the start of the 13th day of disruption by the 4,600 signalling members of the National Union of Rail, Maritime and Transport Workers. A 24- hour strike begins at noon.

If Railtrack fails to persuade many strikers back to work, the dispute could go on for weeks.

Supervisors' rostered days off have been cancelled and shifts reorganised while all signal staff have been approached by management and urged to report for duty.

Railtrack says 40 per cent of the network will be open, allowing British Rail to run the highest number of trains since the dispute began on 15 June.

Nearly all BR divisions yesterday announced new services on strike days but the corporation refused to commit itself to Railtrack's 40 per cent target.

RMT leaders accused Railtrack of a desperate attempt to undermine support for the stoppage which is costing union members about pounds 50 a day in lost wages.

'It's all a softening-up exercise,' said a spokesman. 'They want to deceive signal workers into thinking the strike is crumbling so they can sell the new contracts. It's the only shot they've got left.'

The union believes Railtrack will begin to issue its new contracts over the Bank Holiday weekend and in advance of a 48- hour stoppage scheduled to begin on Tuesday 30 August.

The two sides have not been in contact since the end of July. Railtrack is insisting that negotiations include proposed restructuring while the RMT wants immediate settlement of a pay claim.

Dr Brian Mawhinney, Secretary of State for Transport, has ruled out increasing the cash available to settle the dispute and said any pay rise must be financed through productivity gains.

Railtrack dismissed safety fears raised by Aslef, the train drivers' union, which said it was seeking legal advice over the position of drivers concerned about the competence of some stand-in signallers.

'We will not allow our members or passengers to travel on a railway that is unsafe. If there is a risk we would be prepared to consider taking action,' Lew Adams, general secretary, said.

Frank Dobson, Labour's transport spokesman, said that rail privatisation had so far cost more than pounds 47.5m - nearly 10 times the cost of settling the dispute.

BR figures showed that, since April 1993, it has spent pounds 11.1m on consultants' fees in addition to the pounds 19.9m already spent by the Government. Railtrack said it had spent pounds 16.5m on privatisation.

'The fees handed over to the consultants would settle the dispute six times over,' Mr Dobson said. 'I can't believe that many people think that it's better spent on lawyers, merchant bankers and management consultants.'