The rail line between Aberdeen and Dundee has been closed as engineers deal with a track defect.
Network Rail announced the route had been shut in both directions just before 5.30pm on Tuesday.
ScotRail announced train passengers could expect delays and cancellations as a result of the emergency work.
The rail provider tweeted: “Due to a track defect, services between Dundee and Aberdeen will be subject to delay and cancellation in both directions. The line is now closed whilst @NetworkRailSCOT carry out necessary inspections to the track.”
ScotRail added that rail tickets will be accepted on Stagecoach services between Dundee and Arbroath.
Network Rail said: “Our engineers are responding to a reported track defect on our Aberdeen – Dundee route.
“Whilst we’re carrying out a safety inspection, both lines will be closed. We will provide a further update as soon as possible.”
Updates can be found on the ScotRail website.