Rail passengers have been told to expect disruptions to services across Scotland due to staff shortages.
A lack of train crews resulted in ScotRail cancelling some services with replacement buses operating.
Other services will run on a reduced timetable with a smaller number of stops.
The train operator said its “final push” to deliver timetable improvements later this month was the main reason behind the disruption.
Scotrail informed passengers of the timetabling change through a social media post on Sunday morning.
A ScotRail spokesperson said: “We’re sorry to our customers who have experienced disruption to their journey.
“The majority of the impact is a result of our final push to deliver the December timetable improvements which will bring faster journeys, more seats, and more services for our customers.”
Some of the services affected include trains running from Glasgow to Edinburgh, Inverness and the Kyle of Lochalsh; and between Aberdeen and Glasgow.
The disruptions are expected to last throughout the day.