CSX track work question

[MattW]

I live within a mile of the CSX mainline from Atlanta, GA to Augusta, GA and have noticed them doing quite a bit of tie and ballast work on the line. I was wondering if this was just a standard maintenance cycle, or if they're upgrading the track? They're tearing up and replacing the road surfaces at various grade crossings. The track is already at least Class4 as judged by the speed freight trains travel though there. I've searched several sites but found nothing.

Thanks for any help,

Matt