It's a working industrial branch - previously it served the quarry and accompanying cement plant until those closed in 2009, and has now been reactivated to partially infill the quarry with waste.
There are a few trains each week, hauled by class 66s and operated by DBS (and some GBRf IIRC?). In
this video you can see the normal stock alongside the saddle tank brought in for the open day.
Definitely not a preserved line - a few people have suggested creating one after the quarry infilling is completed, but not with any serious plans to my knowledge.