ScotRail punctuality should be better by March than the level that triggered ministers to order improvements, managing director Phil Verster told MSPs today.
However, the news came as a row erupted over who will pay for pledged free travel for season ticket holders as compensation for ScotRail train delays.
Mr Verster said ScotRail’s performance by March “would clear 90.3 per cent” at least.
The measure is the proportion of trains arriving within five minutes of time over the previous year.
It increased by 0.2 points to 90 per cent over the last month.
However, the figure remains below the minimum acceptable level.
That threshold is increased every month, and was 91.1 per cent for the year to 7 January.
Mr Verster told the rural economy and connectivity committee the punctuality figure should increase further over the summer.
That is because disruption caused by closure of the Queen Street tunnel in Glasgow and industrial action by conductors last summer would no longer be included in the rolling annual figures, or “moving annual average” (MAA).
Mr Verster said they had had a “very clear impact on performance.
“We expect in the second half of the year there will be huge opportunities for improving the MAA.”
Transport minister Humza Yousaf ordered a performance improvement plan when punctuality dropped below 90.3 per cent last September.
Mr Verster said 733 of more than 1,000 “milestone actions” in the plan had been completed.
They include upgrades to trains and tracks to prevent faults, breakdowns and delays.
ScotRail engineering director Angus Thom said replacing couplers which link carriages on one type of electric trains had increased their reliability to record levels.
Several members of the committee raised concern about how a planned one week’s free travel for monthly and annual season ticket holders because of the delays would be funded.
However, the Scottish Government’s Transport Scotland agency insisted it would go ahead.
The fears came after Mr Verster revealed ScotRail had yet to agree to provide £1.8 million for the £3m scheme.
ScotRail’s contribution would come from a rail improvement fund generated by fines paid by the train operator for failing quality checks, such as the state of trains and stations.
Liberal Democrat transport spokesman Mike Rumbles said: “Passengers were told this free week came courtesy of the generosity of the Scottish Government.
“Instead, we find out today it is being funded by a raid on the fund for rail improvements.
“This is a scandalous and fraudulent move by the Scottish Government and passengers deserve so much better.”
Rhoda Grant, a Labour member of the committee, said: “It is increasingly clear Humza Yousaf’s announcement was calculated on the back of a fag packet, and even that might be too kind a description.
“The fact that ScotRail still don’t know how they will pay for the SNP’s plan is astonishing. This is yet another example of too much spin and not enough substance from Humza Yousaf.”
The Scottish Government said it remained “absolutely committed” to the offer.
A spokesman said: “A free week’s travel will be offered this year and further discounts for daily, weekly and leisure travellers.
“The ScotRail contract permits Squire funding to be directed to initiatives that improve the customer service experience, and we are currently negotiating the terms of the fares initiative with ScotRail through Transport Scotland, with the details expected to be finalised and announced in the coming weeks.”
Meanwhile, Mr Verster also revealed the first electric trains could be operating on the main Edinburgh-Glasgow line in May rather than July - although still five months late.
Class 380 trains, which run on lines such as Edinburgh-North Berwick, would initially operate the services before brand new Class 385 trains take over from September.
Mr Verster said: “The Edinburgh Glasgow Improvement Programme is on track.
“We are trying to pull it forward from July to benefit our customers significantly by introducing electric rolling stock for the May timetable change.”
However, the project has been delayed from last December and its cost has increased to around £800 million.
The new trains will also not provide more seats than the current ones until the end of the year, and journey times will not be reduced until December 2018.
Mr Verster said the first of the new Hitachi-built Class 385 fleet had just started overnight testing on the Glasgow-Gourock line and was going “superbly well”.