ScotRail punctuality has improved for the first time in three months despite disruption from staff training and industrial action.
The train operator will also be relieved its average performance over the last year has stopped falling for the first time since May.
However, the latest four-weekly figure of 83.4 per cent is only 0.1 per cent better than the same period last year and worse than in 2016 - the standard industry comparison.
This "public performance measure" reflects the proportion of trains arriving at their destination within five minutes of schedule over the four weeks to last Saturday.
It compares to 80.5 per cent for the previous four-week period and 81.8 per cent in the preceding one.
The "moving annual average", for the year to 8 December, was unchanged at 87.3 per cent.
The latest figure also takes no account of the hundreds of cancellations over recent weeks caused by a backlog of staff training ahead of 100 extra daily services being launched last Sunday.
ScotRail said many of these were "planned" cancellations, along those from an overtime ban by the RMT union, so did not count against punctuality.
But it said they had also triggered some "unplanned" cancellations, which did affect the figures
A spokesman said incidents which had had the biggest impact on performance were a track fault at Corkerhill on the Glasgow-Paisley Canal line, a train fault at Croy on the main Edinburgh-Glasgow line and flooding at Falkirk Grahamston.
He said: "Several weeks of industrial action by the trade union RMT and training for the introduction of the new timetable on 9 December had an impact on punctuality.
"The ScotRail Alliance – a partnership between Network Rail Scotland and ScotRail - has faced a challenging few months, but is committed to delivering the best possible service for its customers.
"The introduction of InterCity high-speed trains and brand-new Hitachi class 385 electric trains, as well as major infrastructure improvements like the electrification of the Stirling-Dunblane-Alloa route, have enabled the delivery of the enhanced timetable.
Managing director Alex Hynes said: “We know it has been a challenging time for Scotland’s railway, but it is encouraging to see our punctuality has improved in recent weeks.
"With the successful introduction of the new timetable, everyone across the ScotRail Alliance is working flat out to keep improving the service for our customers.
“With the first phase of improvements in place, our new trains and infrastructure enhancements, we are working together to deliver the punctuality and quality of service that our customers deserve.”
Scottish Conservatives transport spokesman Jamie Greene said: “After months of having to endure the worst punctuality for over a decade, passengers will no doubt welcome the improved performance figures.
"However, they remain low by historical standards so there is still more work to do.
“At a time when fares are rising, passengers will no doubt feel short-changed by the service that they have been afforded over the last 12 months.
"Delays, disruptions and cancellations have become the norm.
“The Scottish Government must make improving punctuality a priority.
"Passengers are rapidly losing confidence in its ability to manage our railways.”
Colin Smyth, his Scottish Labour counterpart, said: “The news that ScotRail have again only avoided breaching their franchise because the SNP Government have moved the goalposts is a massive embarrassment to transport secretary Michael Matheson.
"Scotland’s hard pressed rail passengers are being let down by delays, cancellations and overcrowding.
“Labour recently forced a vote in the Scottish Parliament asking the government to scrap the ScotRail franchise - but the SNP joined forces with the Tories to vote it down.
"The latest woeful performance figures where one in five trains are running late shows they were wrong.
"This needs to act as a wake-up call to Michael Matheson who has been far too slow to take action."
Scottish Liberal Democrats transport spokesman Mike Rumbles said: “Days of upheaval on Scotland’s railways need to come to an end.
“After months of delays and refits to Scotland’s new trains, ScotRail should not pat themselves on the back for incremental improvements, especially when the headline target for 90 per cent of trains to arrive on time is still not being met.”
A spokeswoman for Transport Scotland, which oversees the ScotRail franchise, said: “In a week where we should be celebrating the biggest increase in services and capacity, enabled by our ambitious electrification programme delivered by Network Rail, instead we are once again talking about performance, albeit slightly improved this period.
"Ministers have repeatedly stated there can be no clearer need for immediate, consistent improvement.
“It must be acknowledged that the recent infrastructure issues, weather, delayed rolling stock introduction, industrial action and staff training all compounded to negatively impact performance.
Some of these issues are now resolved and we anticipate the forthcoming analysis of the ScotRail Alliance’s implementation of the Donovan Review, commissioned by the Office of Rail and Road, will show inroads are being made towards an overall step change.
"Devolution of Network Rail’s activities to Scotland would allow us to take further action to improve services
“Improved capacity and services, brought about by the timetable change, are a welcome progression but more can and must be done to show passengers the ScotRail Alliance can indeed deliver a 21st century railway.“