A significant derailment involving a bulk cement train has blocked lines south and east of Carlisle, bringing significant disruption to all traffic between that northwest junction town and destinations east to Newcastle and south to Leeds. The lines blocked or disrupted are primarily the Tyne Valley line, which runs east-west across the north of England, and the Settle and Carlisle line, which is a critical freight route, reliving the West Coast Main Line. Diversions are in operation.