Trains north of Perth are being disrupted because of the forecast of heavy rain and thunderstorms.
Network Rail says services between the city and Inverness are facing a 40mph speed limit on Friday.
Those travelling with ScotRail and LNER are being urged to check in advance, as the reduced speeds may cause delays and changes to the timetable.
Due to the heavy and prolonged rainfall that's been forecast, we've had to put a 40mph speed restriction in place between:
• Perth and Inverness
• Aberdeen and Inverness.This is likely to have an impact on some services, so check before you travel. @ScotRail @LNER pic.twitter.com/JgrcMi0x6e
— Network Rail Scotland (@NetworkRailSCOT) August 6, 2021
A tweet from ScotRail said: “If you’re travelling today, please be aware that we’re expecting some heavy and prolonged rainfall across the country which may affect some services.
“Keep an eye on the app/Journey Check for the latest service info.”
The line between Aberdeen and Inverness has a similar restriction.
It comes after the Met Office issued warnings for thunderstorms and heavy rain across Tayside and Fife.
A yellow warning for thunderstorms, covering Fife, Dundee and Perthshire is in place for most of Friday.
Looks like the Met Office got it right – it's absolutely stotting down out there. We've not had any reports of flooding anywhere yet, but surface water on roads + overflowing drains are already becoming a bit of an issue. PLEASE take care and plan essential journeys accordingly. pic.twitter.com/YAE2WTtyry
— Tayside Police (@TaysidePolice) August 6, 2021
A second warning comes into force on Saturday morning.
Meanwhile there is also a warning on Friday for heavy and persistent rainfall covering Angus.
SEPA has also issued flood alerts covering Dundee and Angus, Tayside and Fife.