Rail signalling workers are to stage two fresh strikes in a row over career progression following the breakdown of talks.
Members of the Rail Maritime and Transport union based at the West of Scotland centre will walk out for 24 hours from 5.59am on February 14 and from the same time on March 2.
The workers staged a 72-hour stoppage over Christmas but suspended further action to allow for further talks.
The union claims Network Rail is refusing to stick to a long-standing local arrangement where, when a resident post becomes vacant, it goes to a senior staff member.
RMT general secretary Bob Crow said: "RMT has tried to reach a negotiated settlement to this unilateral ripping-up of a local arrangement but unfortunately the management have refused to see sense and have failed to engage with us seriously since the strike action over Christmas.
"RMT members will not stand by while management unilaterally rip up agreements and practices that have been in place at local level for decades. As a consequence of management's continued intransigence we have no option but to go ahead with this further wave of strike action.
"RMT members are furious at this refusal to comply with a local arrangement that offers genuine career progression opportunities. RMT remains available for talks at any time aimed at resolving this dispute."
A Network Rail spokesman said: "We're confident we will run a comprehensive service for passengers if these strikes go ahead.
"More than 95% of services across Scotland ran as timetabled during the last strike. Only a small number of local Glasgow services had to be reduced. We remain committed to resolving the dispute, but cannot meet the RMT's demand that jobs should be awarded on seniority rather than ability.
"Despite the RMT's claim that no effort has been made to resolve the dispute, in reality we met them with Acas in January and reached an agreement which committed both sides to more discussions to resolve the dispute. These discussions had commenced and were progressing constructively, which makes the RMT's sudden call for further strike action difficult to understand."
