Well, I'm glad I'm not alone in this.
I have had all the problems of sprung track, having to go underground to retrieve it, auto pins that won't delete anymore, etc. It gets frustrating as there seems to be no consistency in the way they work.
Someone mentioned that adding pins caused the sprung track problem. That needs to be fixed. Trying to set grade through accurate terrain requires it.
The ability to delete pins at will needs to be there as well as sometimes it is efficient to have a join snap to the average gradient of the two pieces.
Recently I've noticed that if you go in and delete a pin you added in the middle of track length, it may leave the track gradient change in place, not snapping the track back smooth. That is particularly annoying.
In retrieving sprung track I have also noticed phantom pins off in underground space, not attached to any track. They only go away of you raise them above grade. Clearly there is a bug in the gradient tool.