Passengers had less than one week's notice of changes last weekend

The Office of the Rail Regulator says Network Rail has agreed to comply with the requirement by September next year.

Under its licence agreement, Network Rail is obliged to give 12 weeks notice of revisions to any of its timetables.

But over the August Bank Holiday weekend, passengers had less than one week's notice of changes, a delay the ORR called "unacceptable".

Network Rail has agreed to meet a series of milestones between now and the September 2005 target date for full compliance with the 12-week rule.

The situation is improving week by week Network Rail

The ORR says these benchmarks will ensure passengers have accurate timetables for journeys over Christmas this year and Easter and Bank Holiday weekends early next year.

By 20 November, Network Rail will have to provide information on timetable changes four weeks in advance for every day of the week.

That target will rise to six weeks by next March, eight weeks by late May and 10 weeks from late July.

'Unacceptable'

ORR chairman Chris Bolt said: "Experience over the August Bank Holiday has shown, once again, that the current position on the provision of advance timetable information is unacceptable.

"NR is failing to meet its licence requirement to make timetable information available to train operators 12 weeks in advance, so that passengers can plan journeys, reserve seats and access the full range of fares.

"NR has committed to delivering a recovery plan for a staged return to compliance, which ORR will closely monitor. If it fails to deliver that plan, ORR will consider what further action is required."

Engineering work

A spokesman for the ORR told BBC News Online the next step would be for Network Rail to be issued with an enforcement order.

He said if Network Rail made no response to that order, it could face court action from train operators seeking to recoup any losses they may have incurred.

This was the first time the regulator had asked Network Rail to improve its timetable requirement compliance, he said.

A Network Rail spokeswoman said: "We recognise the need for passengers to have as much notice as possible of engineering works and are acutely aware of the consequences when this notice is not possible."

She blamed recent problems on the "unprecedented" amount of engineering work the company is carrying out and said steps have already been taken to improve planning.

"Things are getting better with passengers able to book long distance journeys anything from one to two and half months in advance. It's still not where we would like to be but the situation is improving week by week."