Scottish rail union members have been slammed for planning strike action which would coincide with the start of T in the Park.
The union was criticised for the timing of its action
The Rail Maritime and Transport Union (RMT) intends to strike on 6 July in a row over bonus payments.
Network Rail described the union's timing as "appalling".
The dispute involves about 400 Network Rail signallers in Scotland, who claim bonuses were cut following a previous strike in March.
The T in the Park festival will see tens of thousands of music fans heading for Balado in Perth and Kinross from Friday 6 July to Sunday 8 July.
Two days of rail strike action in March, which was called over demands for a 35-hour working week, saw no trains running north of Stirling.
Network Rail responded to the industrial action by docking discretionary bonus payments to the staff involved.
RMT general secretary Bob Crow told a union conference in Edinburgh on Monday that Network Rail had acted "appallingly" and warned that the dispute could spread.
He said: "We have been trying to get management to reconsider their position but the bosses have said they will not talk to us.
"Our members have been treated appallingly by Network Rail. What has happened in Scotland means that any group of workers going on strike could lose their bonus."
Network Rail chief executive John Armitt said: "On behalf of all rail users, we are angered and extremely disappointed by the RMT's plans for an unnecessary strike.
"Time and again, this union adopts an outdated and divisive approach to managing employee relations which will, once again, serve to punish and inconvenience passengers and rail users."
RMT members in Cumbria have also voted to strike after Network Rail withheld their bonuses in the wake of a Virgin Pendolino tilting train derailing at Grayrigg in February, killing one passenger.
Bonuses for senior executives were reduced by an extra 15%.
The RMT has also decided to hold a strike ballot among its 15,000 members over the treatment of workers.