"Disruption on Northern Rail between Manchester Victoria and Rochdale, between Eccles and Stalybridge and between Manchester Victoria and Salford Crescent due to signalling problem at Manchester Victoria. Fewer trains than usual are able to run on some lines, with some trains terminating at Manchester Victoria. Services through the station are being delayed by up to 20 minutes. There is no estimate for when a normal service will resume."
My bold - fewer trains than usual can go on some lines because of signal problem