Rail journeys to and from Glasgow Queen Street over the next three Sundays will be longer on several routes because of engineering work.
Trains will be diverted via Cumbernauld to avoid track and signalling works at Polmont and at Cowlairs Junction in the north of Glasgow.
Trains to Edinburgh will call at Falkirk Grahamston instead of Falkirk High, and most trains will leave Glasgow earlier or arrive there later.
Services on the Cumbernauld route will be affected, and customers may need to change trains at Springburn.
Services to Stirling, Alloa, Aberdeen and Inverness will also be subject to alterations
Customers are advised to check their journey plans on the ScotRail app or at scotrail.co.uk.
A ScotRail Alliance spokesperson said: “These are vital works, and we appreciate our customers’ patience.”