All lines between Halifax and Huddersfield are blocked due to emergency services dealing with an incident on the track.
Train services between Huddersfield and Leeds via Brighouse are being diverted due to an emergency incident.
National Rail said disruption is expected until 10am.
The line between Halifax and Huddersfield is completely blocked, train operator Northern said.
Train services from Leeds to Manchester Victoria / Southport and Wigan Wallgate will be diverted via Bradford Interchange and will not be able to call at Cottingley, Morley, Batley, Dewsbury, Ravensthorpe, Mirfield and Brighouse.
Rail replacement transport is available at Halifax and Huddersfield.
Services from Leeds to Manchester Victoria via Bradford Interchange and TransPennine services from Leeds to Manchester Piccadilly via Huddersfield are not affected by this problem.