The Association of Train Operating Companies (Atoc) has said the overall average rise, including non-season tickets, will be 3.9% on Wednesday, with some fares not going up as much as this.
But with some non-season-ticket unregulated fares allowed to be increased by an unlimited amount, Railfuture said that some fares could be going up by around 11% or 12%.
From Wednesday, fares are also going up by an average of 4.2% on the Underground and on London buses.
Petrol tax is frozen and overall the cost of driving remains static. How does this help persuade people out of their cars and ease congestion? Where is the green policy?
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Tuesday's weather for the west of the region
Tuesday's weather for the east of the region
The Government has previously described the new coin - which enters circulation on Tuesday - as "harder to counterfeit than ever before".