Network Rail has said that diversions put in place following a landslide near Guiseley Station on Tuesday are expected to remain until Monday next week.
The slope failure, which was spotted by the driver of a Northern train, has caused extensive damage above the portal of the Springs Tunnel.
The driver was alerted to the issue after seeing a tree perching precariously over the southern portal of the tunnel just after 6pm on 3 April.
Since then Network Rail engineers have been carrying out assessments of the damaged tunnel portal and the railway infrastructure as well as making plans to clear away the 80t of fallen debris, which includes large trees and soil.
Repairs are now underway but are likely to take several days, and Network Rail and Northern are advising passengers travelling between Leeds and Ilkley to check before they travel, with alternative arrangements in place.
Network Rail head of operations Chris Gee said: “The downpours of the past week have caused some of the embankment above the southern end of this short tunnel to slip, resulting in around 80t of material moving down towards the railway. Our teams have been working on site 24/7 since the landslip was reported and progress so far has been good.
“We’re working towards getting the direct service between Leeds and Ilkley back up and running by Monday morning and thank those who are disrupted by this incident for their patience and understanding.”