The union action, which will include workers from Huntingdonshire's two stations in Huntingdon and St Neots, is part of a long running dispute over harmonisation of terms and conditions.

The members of RMT - the National Union of Rail, Maritime and Transport Workers - will not book on for shifts between midday on Saturday (July 26) and from 6pm on Sunday (July 27).

Network Rail's director of human resources Peter Bennett said: "We continue to approach negotiations in a positive manner – progress is being made and that is why we believe this strike is pointless and unnecessary.

"There will be no impact on passengers or freight users during the strike as we have thorough and detailed contingency plans in place. Experienced, fully competent and well-trained staff will be out on the track this weekend keeping a full, normal train service running."

RMT's talks team believed it had made sufficient progress to recommend a suspension of this weekend's action.

However, RMT general secretary Bob Crow said a letter subsequently received from Network Rail head office failed to reflect the understandings reached in a number of crucial respects.

Mr Crow said: "It is reasonable to expect that the people you are sitting round the table with have the authority to negotiate, but the progress we thought we had made in talks at Network Rail on Tuesday has simply been vetoed from on high.

"On a range of issues, including pay protection, we believed we had made enough progress to enable the union to call off the weekend's strike, but when we received a letter that was supposed to confirm the progress made, some of the key items were simply not there.

"The only possible conclusion is that someone at a senior level in Network Rail would rather undermine their own negotiating team and see the weekend's strike go ahead than allow the understandings we had reached to stand."