Train users are facing delays on Sheffield trains this afternoon due to signalling problems.
Services leaving Sheffield are delayed or cancelled this afternoon, causing traffic chaos.
Northern Rail has also released details of several services which are being terminated before reaching the city because of the issue.
The following changes are being made to services until further notice.
Trains from Leeds to Sheffield will terminate at Rotherham Central.
Trains from Leeds to Sheffield travelling via Barnsley will terminate at Meadowhall.
The 13.26pm train from Lincoln to Sheffield, due to arrive at 2.47pm will no longer call at Woodhouse and Darnall.
Follow @NorthernRailOrg on Twitter for more updates.