The Government is allowing train firms to raise fares by 3% more than RPI inflation from January, based on July's inflation figure.
Unions have warned that some fares could jump by 11% from the New Year, while most rush-hour travel, season tickets, and off-peak fares will rise by well above the rate of inflation.
Campaigners said commuters to London were routinely spending 15% of their salary on getting to work, and between 2011 and 2015, could see their annual season ticket rise by more than £1,000.
Bob Crow, leader of the Rail Maritime and Transport union , said passengers will be "rightly angry" when they find out the full extent of inflation-busting fare increases imposed on them by Government "diktat".