The landslides on Friday night are expected to prevent trains from running between Ardrossan and Largs until at least Wednesday.
They occurred at West Kilbride and Fairlie, with the latter involving thousands of tonnes of material over a 50m long stretch of track.
ScotRail said trains between Glasgow Central and Largs were only going as far as Kilwinning.
The official ScotRail JourneyCheck information service stated on Sunday: “Disruption is expected until the end of the day on 09/02/21.”
Network Rail Scotland tweeted: “We’re dealing with two significant landslips between Ardrossan and Largs.”
A spokesperson added: “Specialist earthworks, drainage and overhead power engineers are still on-site continuing to assess the damage caused.
“The hillside above the line is also still moving at Fairlie, so we’ll need to continue to monitor the ground conditions before repair works can start.
“There’s damage to overhead line stanchions and potentially to the track, so we’re looking at a significant job.
Meantime, there was disruption for much of Saturday to LNER, CrossCountry and TransPennine Express services after flooding shut the east coast main line at Penmanshiel, south of Dunbar.
LNER said: ”Heavy rain flooding the railway between Edinburgh and Berwick-upon-Tweed earlier today is causing disruption to journeys between these stations.
“Trains are now beginning to return to normal, however, services may still be cancelled, delayed or revised.”
The line re-opened later on Saturday but disruption continued for the rest of the day.