Transport Secretary Chris Grayling has denied railway passengers outside London and the South East are "poor cousins" as he defended the scrapping of plans for electrification in Wales, the Midlands and the North.
Mr Grayling said using "smart technology" and new "bi-mode" trains that run on diesel and electric means the move is "not about cancellation" but modifying plans "where it makes a difference".
Routes between Cardiff and Swansea; Kettering, Nottingham and Sheffield; and Windermere and Oxenholme in Cumbria, will be affected by Thursday's announcement ditching electrification, sparking anger from local MPs.
Labour claimed Mr Grayling was "taking people for a ride" and breaking promises on upgrading the routes.
Mr Grayling said: "What people need to understand is yesterday's announcement was not about cancellation, it's about making use of smart technology.
"What we've got on the railways is technology we didn't have five or six years ago.
"We are not abandoning electrification, what we are doing is using electrification where it makes a difference.
"But when you have got a train that switches seamlessly from diesel to electric, there are places on the network you don't actually need to start digging everything up and putting in place overhead cables, because you don't derive a benefit to passengers.
"Putting an overhead cable in between Cardiff and Swansea will not make the slightest difference to any passengers' experience on that journey.
"It's not about not doing the right thing by passengers, it's about actually using technology in a way that provides the quickest possible improvement and the best possible journeys."
Mr Grayling said Swansea will get new trains this autumn running to London Paddington with improvements to capacity and services.
He denied claims that passengers outside the capital and the South East were not getting their fair share of Government money spent on transport.
A recent study by the Institute of Public Policy Research (IPPR) North, showed Yorkshire and the Humber will get £190 per head, the North East £220, the North West £680 and London £1,940 for transport spending from 2016/17 onwards.
Mr Grayling said the giant £14.8 billion Crossrail project underneath London explained the difference in spend.
He added: "That skews the figures. If we were doing Northern Powerhouse rail, it would be the other way round, people in London saying, 'Why are you spending more in Manchester?'
"You can't just look at Crossrail which does distort all the national figures. It's because we have got this one big project that creates a difference.
"And as HS2 goes north and Northern Powerhouse rail happens, you will see the balance shift the other way."
He said improvements were "happening now" outside the capital, citing the Ordsall Chord in Manchester, linking the city's two main train stations, Piccadilly and Victoria, £300 million of improvements to railways in Liverpool, and investments by Northern Rail, the UK's largest train operator outside London, spending £580 million on 98 new electric and diesel trains.