Rail links on the Highland Mainline are facing “severe delays” on Friday morning due to a signalling fault.
ScotRail warned passengers that due to the issue near Blair Atholl, services running between Perth and Inverness face stunted services.
However, they added that Network Rail staff were working to rectify the problem as soon as possible.
It means services have to run through this area at a slower speed than normal.
The ScotRail website advised passengers that delays are expected to last until around 2pm on August 11, and in the meantime trains may be delayed by up to 50 minutes.