Delayed trains have cost ScotRail more than £100,000 in repayments since the service was nationalised in April, figures from the Scottish Liberal Democrats show.
Figures revealed through a series of freedom of information requests show 7,770 claims were paid out to travellers who had experienced disruption between April and May.
The rail service, which was nationalised by the Scottish Government in April, has forked out a total of £107,439.49 in the two months.
Travellers have been hit by weeks of disruption as ScotRail cut hundreds of services amid a pay dispute between rail unions and employers.
Train drivers’ union Aslef has now accepted a 5% increase from ScotRail, along with more money for rest day and Sunday working, and members will be balloted on the offer.
However a separate dispute over pay, jobs and conditions with Network Rail has caused 40,000 members of the Rail, Maritime and Transport (RMT) union to strike, resulting in significant further disruption for travellers.
In 2018/19, the service, then run by Abellio, reimbursed £87,186.13 in the first two periods.
A total of £165,305.12 was paid out in the same periods of 2019/20, while subsequent years were disrupted by the Covid-19 pandemic.
Under the Delay Repay scheme, ScotRail divides each financial year into 13 periods.
The fee paid out to passengers in the last two months is higher than the equivalent payments in the first two periods of the 2016/17, 2017/18 and 2018/19 financial years, the party said.
And it warned thousands more rail passengers may be due reimbursements but have not made a claim.
Jill Reilly, the party’s transport spokeswoman, said: “Part of the reason that the contract was taken away from Abellio was that thousands of trains were regularly running late.
“This is a significant bill for the service to have racked up in just two months, an ill omen for the state of Scotland’s nationalised railway.
“This only accounts for those who go through the process of applying for a refund.
“The Scottish Government needs to tell taxpayers how much money has been set aside to meet delay repayments and when they think they will have this under control.
“Commuters and rail users need a service that they can rely on if we are to tempt people out of private cars.
“For the good of the planet, the Government must ensure that all services are running once more and that the trains are arriving on time.”
Phil Campbell, ScotRail’s head of customer operations, said: “Providing the best possible service for customers is at the heart of the work we do, and our Delay Repay guarantee is an important part of that.
“We know how much of an inconvenience it is to customers when things don’t go to plan, and it is only right that they are compensated when that happens.
“We’re sorry to our customers for the disruption they have been facing as a result of the reduction in services due to the temporary timetable in place, and we share their frustration.
“We are hopeful that the pay offer will be accepted and encourage Aslef members to vote in favour so that we can refocus our efforts on attracting more people back to the railway as we recover from the impact of the pandemic and deliver for customers.”
A Transport Scotland spokesman said: “When a service is cancelled or delayed passengers are fully entitled to apply for a refund under the ScotRail Delay Repay guarantee and the Scottish Government continues to support this.
“During April and May 2022, services were affected by the temporary timetable in place due to train driver industrial action.
“In Scotland we have worked hard engaging with the employers to ensure the right offer is put on the table to reach a negotiated and agreed settlement on pay.
“We welcome that Aslef intends to present this very good pay offer to members via a referendum with a recommendation to accept.”