Storm Boelo will force rail lines across the west and north of Scotland to close as winds of up to 80mph threaten widespread travel disruption.
Passengers are being urged to travel only if necessary, with services beginning to shut down on Saturday night and speed restrictions being imposed across much of Scotland’s railway network.
The first closures will begin at 9pm on Saturday, when the railway south and west of Kilwinning towards Ayr and Ardrossan will shut.
The Crianlarich to Oban and Fort William to Mallaig routes will close from around 10pm.
On Sunday, the Inverness to Kyle of Lochalsh line will be closed between Kyle and Achnashellach, while the Far North Line will shut between Wick and Thurso and Helmsdale.
Routes closed on Saturday night will remain shut until Network Rail teams have inspected them for fallen trees, debris or other storm damage and confirmed they are safe to reopen.
Speed restrictions will also be imposed across large parts of the network, meaning trains which continue to operate are likely to take longer than normal.
ScotRail has told customers to travel as early as possible and only make journeys where necessary.
No replacement buses will operate on routes suspended because of the severe weather.
Passengers who decide to postpone journeys can use tickets dated Saturday 24 October on Sunday or Monday at no additional cost. Advance tickets are also being accepted on earlier services.
On the Ayrshire routes, the final train from Ayr to Glasgow Central is due to leave at 8.35pm before the line closes. Services between Ayr, Kilmarnock, Girvan and Stranraer are also being affected.
Network Rail said the precautionary closures were necessary because high winds can bring trees and debris onto tracks and damage overhead lines and other railway equipment.
Craig Gorman, head of operational weather strategy at Network Rail Scotland, said decisions to shut lines were not taken lightly, adding: “When we’re facing weather of this scale, we have to put safety first.”
Storm Boelo is the second named storm of the season and follows Storm Austen, which brought heavy rain to parts of Scotland on Friday.
An amber Met Office warning covers much of Scotland, with gusts of 55mph to 65mph expected widely and winds potentially reaching 70mph to 80mph or more around exposed coastal areas.
Heavy rain will add to the problems in northern Scotland, where 20mm to 40mm is expected widely within a separate warning area and totals of 60mm to 80mm are possible in some places.
The storm is also causing disruption to ferry services, while road, air and rail journeys are expected to be affected throughout Sunday.
Passengers have been advised to check the latest ScotRail and National Rail information before setting out, with disruption potentially continuing into Monday on some routes.