Glasgow Subway workers are to take strike action over four days next month.
The first of four 24-hour walk-outs will take place on Saturday, August 6.
The strike will impact on Rangers’ first home match of the season against Kilmarnock at Ibrox.
Unite the union members voted by 99% for strike action on a turnout of 83%.
A 24-hour strike will also take place on Tuesday, August 9, Saturday, August 13, and Saturday, August 27.
It will also impact on Rangers’ fixtures on those days; vs Union Saint-Gilloise (August 9), vs St Johnstone (August 13), vs Ross County (August 27).
Unite say that the dispute centres on subway system operators Strathclyde Partnership for Transport (SPT) enforcing changes to duty schedules.
The union also indicated its members are increasingly being called in to work shifts at short notice, leading to “significant” work-life pressures.
Discussions with SPT have so far failed to give members assurances over family responsibilities and that personal time will be respected, the union has said.
Willie Thomson, Unite Industrial Officer, said: “The strike ballot is a last resort for a hardworking and loyal workforce.
“Time and again the workers have gone above and beyond by keeping the subway running during Covid, and through a time of significant staff pressures.
“Our members are angry about the unfair duty rosters which have resulted in imposed shift changes at short notice.
“This is detrimental to our members’ work life balance. SPT should be in no doubt as to our members’ determination to have these rosters changed.”
Director of Subway, Antony Smith, insisted that SPT remains “committed” to find better ways to work together.
“It is disappointing that this is the course of action Unite members have decided on,” he said.
“Over the last few months, we have had a number of constructive meetings and open sessions with all Subway operations staff to hear their concerns and grievances.
“We only ever re-roster staff at short notice for emergencies in order to keep the system running.
“We have not needed to re-roster staff since the last football match of last season, nor did we during the last three big events in the city.
“We have no plans to do so for the August matches and this has been made clear to staff.
“We remain committed to continuing that dialogue and to finding better ways to work together to deal with issues as they arise.”
Scottish Conservative transport spokesman Graham Simpson said the dates chosen for the strike action had been chosen “cynically” to maximise disruption to Rangers fans.
“The dates for this industrial action have been cynically chosen to maximise the disruption to Rangers fans on matchdays when thousands of them use the subway,” he said.
“We can’t allow a main public transport artery in Scotland’s biggest city to be brought to a standstill by a dispute over duty rosters. These planned strikes must be called off while all parties get round the negotiating table to find a resolution.
“Public transport users have suffered enough already with the unacceptable service cuts at nationalised ScotRail, which the SNP were so slow to resolve.
“If strikes on Glasgow’s underground go ahead, they will merely prolong Scotland’s summer of transport chaos.”
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