Train services in and out of Glasgow Central were cancelled this evening due to heavy flooding.
ScotRail had earlier announced that flooding had forced the closure of the rail line between Barrhead and Kilmarnock.
The train operator said services between Glasgow Central and Barrhead would be cancelled, delayed or revised.
ScotRail tweeted about 7:30pm to confirm that services had started running again on the affected line.
"I'm pleased to advise that the line's now re-opened although speed restrictions are in place," the post said.
"The first service to run was the 6:43pm Glasgow Central to Kilmarnock."
ScotRail staff had headed to the scene of the flooding to review the situation.
Services affected included Glasgow Central to Barrhead, Glasgow Central to Kilmarnock, Glasgow Central to Newcastle/Carlisle via Dumfries, and Glasgow Central to Girvan/Stranraer via Kilmarnock.
A post on Twitter at 5:40pm confirmed buses would be provided for Barrhead and Kilmarnock and would arrive "as quickly as possible".
Network Rail said a landslip at New Cumnock in East Ayrshire was also impacting on train services.
The Met Office has issued a yellow warning of thunderstorms for western Scotland up until the end of today.
Forecasters at the Met Office have issued an all-day yellow warning of heavy rain and thunderstorms, covering a large swathe of England northwards from Manchester, Sheffield and Lincoln.
A section of the A77 in East Ayrshire has also been closed due to flash floods.
Traffic Scotland confirmed the road was shut southbound at Bellfield, with drivers asked to take an alternative route.
The Scottish Environment Protection Agency has a flood alert in place for the region.
It warned heavy and thundery showers were likely to develop that may lead to localised flooding from surface water.
Police Scotland tweeted: "Due to localised storms resulting in heavy rain throughout the West of Scotland, all members of the public are urged to take additional care when driving. #KeepingPeopleSafe."
The Environment Agency has also put out multiple flood warnings and alerts covering central, north-west and north-east England.