Train services across parts of West Yorkshire have been disrupted due to trespassers on the line at Bradford Interchange.
Northern train services said there are already delays of up to 30 minutes for all services passing through the station and the disruption is scheduled to last for at least another hour.
It means there are delays of half an hour on Leeds to Halifax, via Bradford, services.
Some services on the route will be diverted to Batley and not be calling at Bramley, New Pudsey or Bradford Interchange.
A spokesperson for Northern said: "There is currently no estimate as to when the line will re-open."