This video from you tube shows the line still doubled in 1989. I believe it was singled later that year. Which was a massive ricket and 1989 isn't that long ago.
Thanks for this. At some point in the 1990s, the platforms were partially raised along the route, with the unnecessary bits left to grow over. In some cases the recent work has restored the old platform length. In other cases (Shepley, Huddersfield bound) they've extended into new ground doubtless at more expense (on the Sheffield end of the platform) because they'd been short sighted and put railway things in the way on the original bit rendering it unusable.
The line suffers from the single track work that was done then - the timetable isn't optimal as the dynamic passing loop Shepley/Stocksmoor sees things scheduled to meet at the far Sheffield end rather than in the middle.. doh, but that can't be fixed because then things would pass in the wrong place before Barnsley, which also wouldn't be a good idea.