The biggest rail workers' union is planning a series of protests on the day higher rail fares are set to be announced.
Members of the Rail, Maritime and Transport union (RMT) will demonstrate outside more than 30 stations including Cardiff, London, Birmingham, Edinburgh, Liverpool, Bristol and Manchester.
Union activists and campaigners will also step up demands for a publicly-owned railway during the protests on Wednesday August 14.
RMT general secretary Mick Cash said: "RMT activists and supporters will be calling for our railways to be run as an affordable and accessible public service and not for private profit.
"Every year, millions of pounds are siphoned out of the system as private shareholder profit rather than being reinvested in the network.
"Only 10% of stations are fully staffed, yet UK passengers pay some of the highest fares in Europe.
"The increase announced this month will only serve to make the rail network less affordable and accessible for the travelling public.
"Privatisation is at odds with a sustainable rail network - we need a publicly-owned and nationally-integrated railway now."
There has been speculation that the increase in fares will be around 2.7%, which would add more than £100 to the season tickets of hundreds of thousands of commuters.
