The government has scrapped the planned electrification of railway lines in Wales, the Midlands and the North.
Transport Secretary Chris Grayling said the government will instead introduce faster trains with more seats and better on-board facilities.
He said: "We are making the biggest investment in the railways since the Victorian era."
Andy McDonald, Labour's Shadow Transport Secretary, accused him of "taking people for a ride".
Routes between Cardiff and Swansea, and between Kettering, Nottingham and Sheffield, and between Windermere and Oxenholme will be affected.
Mr Grayling said said the new trains on the Great Western and Midland Mainline would be bi-mode, meaning they could run on electrified sections of track and then transfer to non-electrified sections.
He said: "Thanks to this new technology disruptive electrification works... will no longer be needed.
"Passengers will benefit sooner and experience less disruption compared with putting up intrusive wires and masts along routes where they are no longer required."
However, Mr McDonald said: "The Tories have been promising the electrification of the Great Western Mainline from Paddington to Swansea since 2012 and today's announcement confirms that they have been taking people for a ride."
Analysis By Richard Westcott, Transport Correspondent
Eight years ago Network Rail dramatically over-promised how quickly and how cheaply it could electrify some of Britain's busiest rail lines.
Reality soon hit home.
A recent report by the Public Accounts Committee described the electrification of the Great Western line as "a stark example of how not to run a project".
The budget went from £874m in 2013 to £2.8bn two years later.
Why? Because when Network Rail first did their sums, it was based on guesswork. They hadn't looked in detail at what needed doing and it was just much harder than they thought to upgrade Victorian bridges and tunnels on a line that was being kept open at the same time.
So having kicked some of the promised electrification schemes into the long grass a while ago, the government's finally chopped them.
New trains which are part diesel, part electric, will be used instead.
Liberal Democrat Shadow Transport Secretary, Jenny Randerson, said: "The Liberal Democrats secured vital investment for rail electrification when in government.
"That was then delayed by the Tories and now has been scrapped altogether."
The government said it would introduce new Intercity Express trains in Wales with around 130 more seats and faster services.
Wales' Economy Secretary, Ken Skates, told Radio Wales' Good Morning Wales programme: "I don't buy it."
He accused the UK government of "years of broken promises" and said Mr Grayling had not responded to his requests for a meeting on the issue.
"I'm urging the UK government to clarify the situation immediately," he added.
The Department for Transport said the new services meant long distance journey times from Nottingham and Sheffield would be reduced by up to 20 minutes in peak periods.
It said four direct services a day in each direction between Windermere and Manchester Airport will be introduced from May 2018.