The Campaign for Better Transport's campaign director, Richard Hebditch, has said that rail passengers are likely to be £100-200 worse off next year as a result of fare rises.
Speaking on BBC Radio 4's Today programme, he called for the government to end above-inflation fare rises.
Rail passengers are not getting value for money despite numerous hikes in ticket prices, the TUC has said.
Kevin Rowan, head of public services, told Daybreak rises are unjustified when taxpayers were not "seeing the kind of investment we want in the rail industry".
Inflation figures are expected to remain high today, pushing up prices at petrol pumps and leading to rising rail fares.
Retail prices index (RPI) figures are expected to remain high today, pushing up prices at petrol pumps and leading to rising rail fares.
It would give train companies licence to push through regulated price rises of 4.3% next year as they are allowed to rise one percentage point above July's RPI measure.
The consumer prices index is set to remain at around 2.9%.
The Government has defended its track record on rail fares and promised to announce further measures to ensure "greater fairness" for travellers.
A Department for Transport spokesman said the Coalition were investing "record amounts" in the railways and recognised current prices were "tough".
Train users will be forking out 40 percent more than they were six-years-ago for a ticket, say rail campaigners staging nationwide demonstrations later today.
A fare rise scheduled for January will be the sixth time in seven years ticket prices have outstripped wages, say TUC and Action for Rail.
While fares have increased by 40 percent, wages have only rise by 15 percent, it was claimed
The TUC have blamed privatisation for the spike in train fares, General secretary Frances O'Grady said:
"Ministers must put evidence before ideology, halt the privatisation of the East Coast mainline and look at bringing our railways back into public ownership."
Train fares are set to rise yet again on the back of the release of July's inflation figures, forcing rail passengers to fork out more for travel in 2014.
Inflation as measured by the retail prices index (RPI) is expected to remain at 3.3 percent for July, giving train companies the opportunity to push through a price rise of 4.3 percent at the beginning of next year.
The Government determines rail price rises by allowing fares to rise one percentage point above July's RPI measure.
Rail passengers were already dealt a blow with 2013 prices. This year the cost of a season ticket rose by 4.2 percent and overall train fares increased by around 3.9 percent.
First Group, which runs the Great Western Rail Service, will keep the franchise for a further three years.
The new timetable for rail franchise bids was announced by the Transport Secretary this morning.
First Group was due to bid again this October for the service operating trains from the West Country to London Paddington. This has now been delayed and they won't have to bid again until July 2016.
First Great Western have just told us that buses are in place for travel between Swindon to Didcot, Swindon to Gloucester and Bath to Swindon, should passengers want to use them. There are reduced services running between Cardiff and Bristol to Paddington, with trains diverted via Newbury.
ITV News journalist Guy Phillips has just sent us the latest on his attempt to go to Wales. We "We are now boarding a train back to Reading. Great Western hope to get passengers from Reading to Wales via Bath - the long route."
Passengers trying to get to Cardiff are now heading from Didcot back to Reading, following a power failure in Swindon.
Passengers trying to get to Cardiff are now heading from Didcot back to Reading. Those going to Swindon and Bristol are awaiting a fleet of buses to help them reach their destination. Trains from Reading to Wales will go a long route.