There's the double junction just to the north of Morpeth station leading south-east to Bedlington and Blyth, but both standard gauge. There are also a few sidings on that side there, one of which is electrified and the track work looks complex from the level crossing, perhaps giving an odd view of the rails.
A little further north, north of the Wansbeck Viaduct, you would have passed a disused spur eastwards to Ashington, again, this was standarg gauge.
A little further north again, there's will have been odd spur on your east side, to the north of Ashington, odd in that it runs paralell to the mainline for 1km before turning east. Again, standard gauge.