ScotRail officials said they were "still assessing" the impact of strikes by RMT members in Network Rail, but it is "likely" services will face the same level of disruption seen when rail workers downed tools for three days last month.
The operator is still operating a temporary timetable after a dispute with drivers union Aslef where workers refused to work overtime or on rest days as a removal of goodwill over pay and conditions.
Earlier this week, Aslef accepted a five per cent pay rise. ScotRail says teams are working hard to re-introduce the full timetable as quickly as possible and depends on drivers returning to work rest days and overtime.
On Wednesday, it confirmed the timetable would still be in place when Gerry Cinnamon plays at Hampden Park in Glasgow on Saturday and Sunday.
On Wednesday, it was announced workers in the RMT union are to stage a fresh strike in the bitter dispute over pay, jobs and conditions, threatening travel chaos at the height of the summer holidays.
RMT members at train companies and Network Rail will walk out for 24 hours on July 27.
Union leaders made the announcement after rejecting a new offer from Network Rail which they described as "paltry".
The offer was for a 4 per cent pay rise backdated to January, another 2 per cent next year and a further 2 per cent conditional on achieving "modernisation milestones".
The RMT said it has yet to receive a pay offer or guarantees over job losses from the train operating companies (TOCs), and said it will be consulting other unions that have delivered mandates for strike action in the coming days, amid talk of co-ordinated walkouts.
Members of the drivers' union Aslef and the Transport Salaried Staffs' Association (TSSA) at train companies have backed industrial action in recent days.
RMT general secretary Mick Lynch said: "The offer from Network Rail represents a real-terms pay cut for our members and the paltry sum is conditional on RMT members agreeing to drastic changes in their working lives.
"We have made progress on compulsory redundancies, but Network Rail are still seeking to make our members poorer when we have won in some cases double what they are offering, with other rail operators.
"The train operating companies remain stubborn and are refusing to make any new offer which deals with job security and pay.
"Strike action is the only course open to us to make both the rail industry and Government understand that this dispute will continue for as long as it takes, until we get a negotiated settlement.
"The public who will be inconvenienced by our strike action need to understand that it is the Government's shackling of Network Rail and the TOCs that means the rail network will be shut down for 24 hours."
The RMT held three strikes last month which crippled services across the country.