Rail workers are to stage a protest in Birmingham today warning passengers they are paying "more for less" ahead of news on how much rail fares will go up next year.
Commuters and other passengers will find out today how much extra they will be charged from the new year.
The Government links the annual January rise in Britain's regulated fares with the previous July's Retail Price Index (RPI) measure of inflation which will be announced by the Office for National Statistics (ONS).
Regulated fares make up almost half of all tickets and include season tickets, standard returns and some long-distance, off-peak returns.
They increased by 1.9 per cent in January this year but the RPI figure for July 2017 is expected to be around 3.9 per cent which would lead to the highest increase in rail fares since 2012.
Public transport campaigners have called for the Government to use the Consumer Price Index measure of inflation to set rail fares instead.
CPI is generally lower than RPI and is used to calculate changes in benefits and the ONS warned last month that RPI was "flawed" and had "serious shortcomings".
Rail unions said that, even as fares rose, rail engineering work was being delayed or cancelled, skilled jobs were being lost and staff numbers were being cut on trains and at stations and in ticket offices.
Unions are calling for reduced fares, public ownership and protection of jobs during the protests which are taking place nationwide.
They come less than a week after the Government announced a £1 billion investment into the West Midlands' rail network as part of a new franchise awards for the routes currently operated by London Midlands.
A joint venture between Dutch group Abellio, East Japan Railway Company and Japanese conglomerate Mitsui & Co has won the nine-year tenure.
Manuel Cortes, leader of the Transport Salaried Staffs Association, said: "When the Tories passed legislation which allowed rail fare hikes year in, year out, they made legal one of the greatest train robberies in railway history.
"Now, the state-owned railway companies of France, Germany, Holland and Italy, who have gobbled up large swathes of our network, are allowed by Transport Secretary Chris Grayling to laugh all the way to the bank at our expense.
"Train companies, with the Government's blessing, hide behind the Retail Price Index as a method of legitimately fleecing more money from hard-pressed passengers at the start of each new year."
In response, a spokesman for the Department for Transport said: "The Government carefully monitors how rail fares and average earnings change and keeps under review the way fare levels are calculated.
"We are investing in the biggest rail modernisation programme for over a century to improve services for passengers - providing faster and better trains with more seats.
"We have always fairly balanced the cost of this investment between the taxpayer and the passenger.
"We are driving the industry hard to improve efficiency to ensure we maximise the value of passengers' and taxpayers' investment in the railways.
"Regulated rail fares are capped in line with inflation for next year. In the five years to 2019, Network Rail is spending more than £40 billion to maintain and improve the network.
"On average, 97 per cent of every £1 of a passenger's fare goes back into the railway."