Demonstrations are being held at railway stations across the country on Tuesday, to protest against "massive" fare increases.
Unions, transport campaigners and rail passenger groups have launched a day of action to make a stand against rising ticket costs and cuts to jobs and services.
The Government is allowing train firms to raise fares by three per cent more than RPI inflation from January, based on July's inflation figure, which is published on Tuesday.
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".
Rail unions have warned that some fares could jump by 11 per cent from the New Year, while most rush-hour travel, season tickets and off-peak fares will rise by well above the rate of inflation.
Up to 20,000 jobs in the rail industry are at risk under cost-cutting proposals, which will hit station staff, guards, catering and ticket offices, unions said.
Union officials at today's protests will step up demands for the railways to be returned to public ownership, saying that privatisation has led to some of the highest fares in Europe despite a massive increase in taxpayer subsidies to the industry.
Transport Secretary Justine Greening said: "I am keen to see what we can do to keep rail fares down to something affordable.
"I shall be looking at whether there is a way of doing that in the autumn but we have to stick with our deficit-reduction policy."