It runs some 112 km (70 miles) from Bowness-on-Solway north of Carlisle in the west, to Wallsend, just north of Newcastle-upon-Tyne, in the east.
Newcastle-upon-Tyne is north of Wallsend. 
mnli hypothesis: Newcastle-upon-Tyne is north of Wallsend.  premise: It runs some 112 km (70 miles) from Bowness-on-Solway north of Carlisle in the west, to Wallsend, just north of Newcastle-upon-Tyne, in the east.