All rail lines between Leeds and Dewsbury are currently blocked due to a broken rail - disrupting travel between Leeds and Manchester
Northern Rail said trains running between Leeds Station and Dewsbury could be cancelled or delayed.
The disruption is set to last until 12.30pm.
Northern Rail said: "Services between Leeds and Manchester Victoria are currently being disrupted due to a broken rail in Morley tunnel.
"These services will be diverted via Bradford so will no longer call at Morley, Batley, Dewsbury, Mirfield and Brighouse'.
The train company said staff are estimated to arrive on site immediately.
Replacement transport has been requested, Northern Rail said.