Unions, transport campaigners and rail passenger groups have launched a day of action to protest at "massive" fare increases and cuts to jobs and services.
A series of demonstrations will be held at railway stations across the country to coincide with news of another fare increase.
The government is allowing train firms to raise fares by 3% more than RPI inflation from January, based on July's inflation figure, which is published today.
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% 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.
Stephen Joseph, chief executive of the Campaign for Better Transport, said: "If the government sticks by its policy, rail fares will rise three times faster than salaries. With the economy flat-lining, this is untenable.
"The government knows they can't continue to hit commuters - that's why they've postponed the fuel duty increase. Now they need to give the same help to rail users."
TUC deputy general secretary Frances O'Grady said: "These fare rises will add even more pressure to passengers already feeling a massive squeeze on their incomes.
"The government is asking train operators to make cuts to staff on trains, stations and in ticket offices while continuing to receive public subsidy and give millions in dividends to shareholders."
Mr Crow said: "The case for renationalising our railways, and throwing the extortionists and rip-off merchants off the tracks, is now overwhelming. The public is sick and tired of being charged through the nose to travel on creaking, overcrowded trains while the rail companies are robbing them blind."
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."
Ms Greening was asked whether there would be Treasury money available for rail that would enable the fare rise to be reduced. She replied: "Well, if you don't ask, you don't get."
Campaigners said commuters to London were routinely spending up to 15% of their salary on getting to work. By 2015, this will create a series of "£1,000 towns" - places where commuters will see the cost of their annual season ticket rise by more than £1,000 between 2011 and 2015.
Protests will be held at over 40 stations, including Waterloo, Euston and Kings Cross in London, Birmingham New Street, Newcastle upon Tyne, Liverpool Lime Street, Crewe, Glasgow Central and Edinburgh Waverley.
Michael Roberts, chief executive of the Association of Train Operating Companies, said: "The government decides the average increase of commuter ticket prices and other regulated fares which train companies will be required to introduce in January 2013.
"It has been government policy during the past eight years for passengers to pay a larger share of the cost of operating the railways and to focus taxpayers' money on investing in longer term improvements to the network.
"Any flexibility train companies have within the rules is to maximise revenue for the government."