Here's what the status is, as of January 17. It looks like it's going to be the first high level platform on the lower-level through tracks. Note how the grade on the new track is at a significantly lower level than that of the existing tracks. I wonder if they're going to do that to all the lower level tracks. Also, they're going to need to keep at least one low-level platform down there for use by the VRE trains, and the Capitol Limited, which sometimes usues the lower level tracks.