Rail commuters face increased crowding at peak times until planned investment in new carriages and longer stations is completed, the government's spending watchdog said yesterday.

They can also expect to pay higher fares, the National Audit Office (NAO) said in a report on rail company franchises.

The government announced plans last year for 1,300 extra carriages as well as investment to alter junctions and lengthen platforms to allow operators to run longer trains.

Taken together, these measures aim to increase rail capacity by a fifth by 2014 but until then long-suffering commuters, particularly in London, face a peak time crush, the watchdog said.

Fares will also rise as operators seek to encourage passengers to travel outside peak hours and the increasingly crowded "shoulder peak" times.

Last year, for example, Stagecoach South West Trains increased by 20 per cent fares for passengers travelling to London after the morning peak but arriving before 11 a.m.

Fares regulated by the Department for Transport - 43 per cent of the total - are also set to rise on average one percentage point above inflation, as measured by the retail price index.

"Travelling by rail is still too often an unpleasant experience," said Edward Leigh, chairman of the Committee of Public Accounts, to which the NAO reports.

"The news that fares are likely to rise above inflation in these difficult times will infuriate many passengers who have no alternative but to travel day after day on packed trains."

A spokesperson for rail consumer body Passenger Focus said operators should use lower fares to encourage passengers to travel at quieter times, rather than penalising them with high rates for journeys during busy periods.

The Department for Transport said there had been record levels of rail passenger growth over the last decade and that increasing capacity was a priority.

"That is why over £10 billion is being invested to tackle the crowding problems currently experienced by passengers," it said.