Train fares will rise ahead of inflation for another year, the government has announced.
The 3.5 per cent rise will come into force next January.
But some companies could use a "flex" rule to raise prices by an extra 2 per cent.
Martin Abrams, of the Campaign for Better Transport, said: "The expense of taking the train to work has become a huge part of living costs.
"If the government doesn't put an end to above-inflation fare increases quickly, ordinary commuters will be priced off the train."
Transport Secretary Patrick McLoughlin defended the rise.
He said: "We fully recognise there's more to do to bring down the cost of rail travel in Britain."
"But we need to do it responsibly and we can't spend money we don't have."
This year ministers capped fare rises to keep them level with inflation.
No such plan has yet been announced for the 2015 rise.