School summer holidays could be disrupted as East Midlands Trains faces a four day strike as workers are set to walk out in a row over pay.
The trade union Unite said 80 of its members across three depots will stage the industrial action from 0600 on 27 July, ending at 0559 on 31 July.
The union said it predicted that train services would be disrupted during the big "get away" weekend of the summer holidays, as schools break up.
Unite members made the move after East Midlands Trains offered employees a "paltry" 2.75% pay offer for the year April 2014/April 2015 – above the most recent Consumer Price Index inflation rate of 1.9%.
"Our members have worked hard for this company adapting to the many changes asked of them," said Mick Millichamp, Unite regional officer.
"However, they were very disappointed with the current paltry pay offer, now withdrawn, at a time when household bills are going through the roof.
"The management has not applied equal treatment to this group of workers as other groups of employees have received greater improvements to their terms and conditions.
But Tim Sayer, engineering director for East Midlands Trains, said: "We're very disappointed that Unite has chosen to take this course of action, clearly attempting to cause disruption to our customers during the start of the main summer holiday season.
"This action will ultimately hit the pockets of Unite's members and will see no winners.
"We have put forward a very reasonable and fair offer to our engineering staff, representing a 2.75% pay increase, and are extremely surprised that this offer has been rejected."