The EU has accused the UK of potentially breaching the terms of its Brexit agreement with the new crackdown on strike action.
Brussels is considering triggering a formal dispute with the UK Government as a result of the new minimum service laws.
The new strike laws allow train operators to force staff to attend work, in order to ensure they can run up to 40 per cent of their usual services.
It is aimed at reducing the disruption caused by walkouts.
The EU has accused the UK of potentially breaching the terms of its Brexit agreement with the new crackdown on strike action
While it came into action last summer, train companies have been unwilling to use them.
Bureaucrats in the EU have accused the UK of watering down workers’ rights, something which is prohibited under the Brexit deal.
UK officials have said the new legislation is “compliant” with the terms of the deal as it does not “have an impact on trade or investment”.
An EU sources told the times that the commission is not satisfied with the UK’s explanation of the plans, saying the bloc is “looking into” the prospect of taking further action.
Train drivers belonging to the Aslef union staged a walkout region-by-region over the course of last week, from Tuesday 30 January to Monday 5 February.
Thousands of trains were cancelled each day.
Labour has pledged to repeal the minimum service legislation if it wins the next election.
But Former Brexit minister David Jones accused the party of “meekly obeying EU diktats”.
He said: “Minimum service levels are essential to ensure that disruption to the public by industrial action is not allowed to exceed reasonable levels.
UK officials have said the new legislation is “compliant” with the terms of the deal as it does not “have an impact on trade or investment”
“It is about time that the EU recognised that the economic difficulties they are currently experiencing will continue unless there is reasonable regulation of industrial relations.
“Fortunately, their rules don’t apply in the UK, but there is no doubt that they would be adopted if Labour were to win the next election.”