Some 40,000 railway workers, working for Network Rail, the public manager of the rail network, but also 14 private train companies, are observing a four-day strike at the call of the RMT union.
The train drivers' union, Aslef, calls for an additional day of walkout.
RMT, which in June launched the biggest strike in 30 years in the sector, is asking for better wages in the face of inflation which is close to 11% in the country, but also guarantees on working conditions.
The union accuses the Conservative government of blocking negotiations.
Network Rail has warned that "serious disruption" is expected across parts of the rail network this week, calling on Britons to "only travel if absolutely necessary".
The minister assures "working hard" to resolve the conflict between the railway companies and the unions, and indicates that an offer is on the table.
But for the secretary general of the RMT, Mick Lynch, it is on the contrary the executive which "undermines the efforts to obtain an agreement", by imposing too strict conditions on the negotiators of the railway companies.
"We cannot accept the current proposal. We need new elements in the equation to be able to find solutions," he said, believing that an agreement "is possible in the coming days".
Purchasing power strikes have multiplied in many sectors in recent months in the United Kingdom, notably affecting health in December with a strike by nurses and then paramedics, but also postal workers and telecom operators.
Transport has already been disrupted during the holidays by strikes by railway workers but also by traffic officers on British motorways and border police, who have forced the deployment of soldiers at several British airports.
© 2023 AFP