Flooding has forced the cancellation of trains on the main rail line to the Highlands today.
Tracks were under water at the Slochd summit between Carrbridge and Inverness after heavy rain.
In a separate incident, a broken rail at Taynuilt halted trains between Glasgow and Oban.
On the Highland Main line, trains to and from Edinburgh and Glasgow were unable to get further north than Aviemore.
However, one of the two lines was later re-opened under reduced speed.
Services halted included the 08:45am Inverness to Glasgow Queen Street.
ScotRail reported: "Due to heavy rain flooding the railway between Inverness and Carrbridge all lines are closed.
"For safety reasons, the line has been closed.
"Staff are on site monitoring the flooding and will advise when it is safe to run trains again.
"Train services between Edinburgh, Glasgow Queen Street and Inverness will be terminated at and started back from Aviemore.
ScotRail said disruption was expected to continue until 4:15pm.
It said passengers would be switched to replacement buses in Inverness and Perth.
Network Rail Scotland said a passing loop on the mainly single-track line was flooded at the 1,315ft summit, the second highest on the route.
A spokesman said: "At 8:10am, it was reported there was standing water covering a 100m stretch of the Highland Main Line at the north end of Slochd loop.
"The line was closed as the water was at the height of the rail head in places and had also submerged a set of points.
"We currently have engineers on site inspecting the track and were able to reopen the main line at a reduced speed at 10:25am, but the down loop remains closed as water is continuing to flow into that area of the track.
"Our engineers are working to fully reopen the line as quickly as possible for our customers.
"Flood waters can pose a real danger to rail safety – dislodging the track bed or damaging signalling systems.
"We'll need to check if any of the ballast has been dislodged [under the rails] or any damage caused to the tracks, which could extend the timescale for the full line being re-opened."
On the Oban line, trains were halted between Oban and Crianlarich after the damaged rail was reported, with disruption expected to continue until 5pm.
Network Rail said it was a broken fishplate - a piece of metal which is used to bolt two lengths of rail together.