The proportion of train journeys in Britain on publicly run services will hit 25% on Friday.
Analysis by the PA news agency revealed that the milestone will be achieved once the Scottish Government takes over ScotRail.
This is the highest percentage since the privatization of Britain’s railways in the mid-1990s.
The figure highlights “the total failure of the privatization of rail”, according to the union RMT (Rail, Maritime and Transport).
The current situation contrasts sharply with that of four years ago, when no operator was in state hands.
Financial or performance issues have led to growth in public sector operations.
London North Eastern Railway (LNER) was the first of the current generation of public brands to be established.
It resumed running trains on the East Coast Main Line in June 2018 after the franchise held by Virgin Trains East Coast – a joint venture between Stagecoach and Virgin Group – was prematurely terminated due to continuing financial difficulties.
Services on the Northern Network became public property in March 2020 due to long-term issues with punctuality and reliability while the trains were operated by Arriva.
The Welsh Government took over the Transport for Wales franchise from a partnership between Keolis and Amey in February 2021 to provide long-term financial stability amid reduced travel demand caused by the coronavirus pandemic.
Rail services on the South East network were taken over by the government in October 2021 after franchise holder Govia failed to declare more than £25million in taxpayer funding which should have been returned.
ScotRail’s services will be provided by the public sector from Friday, with the Scottish government saying it would not be “appropriate to award a franchise agreement to any party” once the existing deal with Abellio expires.
In spring 2018, 59% of journeys were made by operators owned by foreign companies and 41% by operators controlled by British companies.
From Friday, this will be split between overseas organizations (46%), UK businesses (29%) and the public sector (25%).
The calculations are based on data from the Office of Rail and Road showing that 197 million journeys were made on these five networks last year, out of a total of 795 million.
RMT General Secretary Mick Lynch told PA: “It was the total failure of railway privatization that has seen this gradual but accelerated return to public ownership.
“Privatization has never been more than a money-making racket, and RMT will continue to push the demand to weed out greedy middlemen and renationalize the lot.”
Manuel Cortes, General Secretary of the Transport Salaried Staffs’ Association, said: “The government should realize that rail services work best when they are publicly owned.
“Privatization is a costly failure. Wales and Scotland are doing the right thing and putting services under public control.
“The Conservatives need to abandon their costly obsession with privatization and instead of stuffing money into shareholders’ pockets, put it into our public transit rail services.”
Under rail franchising, the UK, Scottish and Welsh governments have traditionally specified what they want private companies to do over a given period, such as managed services and introduced upgrades.
Companies submitted bids for the right to operate franchises and governments selected the winners.
The UK government presented major reforms to Britain’s railways in the Williams-Shapps plan for rail in May 2021.
This included replacing the franchise system with a new public body named Great British Railways, issuing passenger service contracts to private companies to run trains.
No date has been set for the start of this process.
The Rail Delivery Group, which represents operators, said in a statement that the industry “has long called for reform”.
He added that he was working with the UK government to ensure rail companies “have the right levers to drive innovation and attract more passengers”.
Railway Minister Wendy Morton said: ‘Trains have kept the UK moving for almost 200 years, and Great British Railways will soon be offering a greener, simpler and fairer service to give passengers even greater confidence to plan more of their train journeys.
“What is needed is simplification, not nationalization, and our new model will benefit from the best of the private sector – competition, innovation and investment – to ensure passengers come first.”