The MTA Capital Construction Mega Project Flickr account https://www.flickr.com/photos/mtacc-esa/albums
has shown a lot of work at Harold Interlocking, including new track and switches. I don't know the area well enough to tell where these new tracks are. It doesn't seem like there's enough open space there to put any new tracks.
It would appear that a track is being put in for the Amtrak Westbound bypass, at least for a portion of it. However it's my understanding that the tunnel under the two inbound lines hit a snag, so the bypass track can't go too far.
There's also a large space where two tracks are going in. I don't see any catenary overhead, so it must be LIRR east bound tracks.
It would be nice if someone on this board took video from the front window (or a side window if that gives a better view) and posted it to Youtube!