Trains travelling between Dundee and Aberdeen are being cancelled due to an issue on the line in Angus.
A signalling system fault near Arbroath is affecting services travelling between the two cities.
The issue emerged at about 6.25pm.
ScotRail says there will be disruption until at least 8.15pm.
Network Rail are on the scene.
The 6.46pm Arbroath to Dundee and the 7.38pm Arbroath to Dundee trains have been called off.
Other services running through Arbroath Stations could be subject cancellation, delays or revisions.
ScotRail posted: “We are dealing with a signalling issue at Arbroath. Our staff have been mobilised and will arrive on site shortly.
“Once we have more information from the ground we will keep you updated. Check back here regularly for updates.”
NEW: Our colleagues @NetworkRailSCOT are dealing with a signalling issue at #Arbroath. Staff have been mobilised and will arrive on site shortly. Once we have more information from the ground we will keep you updated. ^Ste pic.twitter.com/XX3lbIzHaf
— ScotRail (@ScotRail) September 18, 2019