During pre-planned engineering work between Garsdale and Kirkby Stephen, a retaining wall collapsed on to the line.
Whilst urgent track repairs are carried out in the area, trains will have to run at reduced speed between Skipton and Appleby.
As a result, services may be delayed.
This is expected to be the case until the end of the day (Monday 23 February)
Northern services between Skipton and Lancaster are not affected.
