Northern Rail has reported that a significant landslide between Guiseley and Kirkstall Forge has affected rail services between Ilkley and Leeds.
The rail operator has said that Network Rail engineers are on site assessing the issue and services are currently being re-routed via Shipley resulting in delays or cancellations.
In a statement, Northern Rail said: “This landslip occurred near the railway and moved a tree so that it has become unstable.
“Network Rail is on site now working to clear the tree from the line and ensure that it is safe for trains to run through, and as a result of the direct line from Ilkley to Leeds is blocked.
“Network rail specialist staff have been closely monitoring the affected site and have now advised that for safety reasons electric trains will not be able to run between Ilkley and Bradford Forster Square in both directions. Cancellations and alterations will occur as diesel trains are put in place of electric trains.”