Rail fares have increased by an average of 3.1% in England and Wales - and almost 3% in Scotland - despite a raft of issues on the network in 2018.
Rail fares rise by 3.1% in England and Wales
The rail industry says 98p of every pound spent on a ticket is invested back into the network.
But Wednesday's price hike was called "yet another kick in the wallet" by campaign group Railfuture.
Transport Secretary Chris Grayling said the government had made a "record investment" in rail.
He also announced that a new railcard extending child fares to 16 and 17-year-olds in full-time education or training will be available by September.
A discount railcard for 26 to 30-year-olds will go on sale from 12:00 GMT. Like the existing card for 16 to 25-year-olds, it costs £30 and reduces fares by a third.
Fares in London will stay the same after a decision by Mayor Sadiq Khan to freeze Transport for London prices.
Protests against rises elsewhere are expected outside stations across the country from rail unions, politicians and campaigners.
The rise in England and Wales - the highest since January 2013 - will see the price of some annual season tickets go up by more than £100.
Analysis from the Labour Party of more than 180 routes claimed that since the Conservatives came into power in 2010, the average commuter is paying £786 more for their annual season ticket.
The increases come despite one in seven trains being delayed by at least five minutes in the past 12 months - the network's worst performance since September 2005, according to the Press Association.
Chaos caused by new timetables from Northern and Govia Thameslink added to problems of extreme weather, strikes and signal failures hitting routes across the country.
Shadow transport secretary Andy McDonald said the latest increases were "an affront to everyone who has had to endure years of chaos on Britain's railways".
Around 45% of fares are regulated by government, and capped at July's retail price index inflation figure - 3.2%.
Other increases are decided by the train companies.
The government has said that fares could rise in line with a lower index of inflation if unions agree that rail workers' wages also increase at a lower rate.
Transport secretary Chris Grayling told the BBC: "I don't think it's right and proper that you see pay rises at 3.5% or more on parts of the rail network that are the biggest factor behind the fare increases."
He apologised for "tough moments" on the rail network in 2018 but said new trains being introduced in London, Birmingham and the north of England showed the impact of "massive investment" by the government and private sector.
'Value for money?'
The UK's railways are predominantly funded by customers' fares: last year's figures from the Office of Rail and Road show they yield £9.7bn, while the government provides £6.4bn - excluding loans from Network Rail.
However, almost a third of the government funding was given specifically to the HS2 high-speed rail project.
Robert Nisbet, regional director of the Rail Delivery Group, which represents the rail industry, said that 11 of the 17 railway companies would be introducing new rolling stock this year.
He said: "What we're seeing on the railway at the moment is a record level of investment, more money being ploughed into the railways than at any time since the Victorian era. That money has to come from somewhere."
But Rail, Maritime and Transport union general secretary Mick Cash said fare payers are being "battered by the toxic combination of gross mismanagement and profiteering".
And campaign group Transport Focus said only 45% of passengers were satisfied with the value for money of their tickets.
Chief executive Anthony Smith told the BBC: "We passengers are putting over £10bn a year into the railways through our fares, on top of the huge amount that the taxpayer is putting in as well.
"Surely that should translate into a better, more modern railway, with more efficiencies, which should be passed back to the passengers in terms of a fares freeze?"
The Department for Transport has also commissioned former British Airways chief executive Keith Williams to carry out a review of Britain's railway network - including fares.
Mr Smith said the review should aim to introduce part-time season tickets and make better use of off-peak trains to boost revenue through higher passenger numbers.