Some closer maps and commentary:
Follows the TRE corridor mostly between D and FW. Love the loop route into DFW. South of D follows the old MKT corridor.
Blue line follows old railroad corridor, red line in brand new corridor.
Blue line follows UP (ex-MP) corridor, red line follows ex-MKT corridor.
Note: the Red line basically gets to the airport using my suggested routing to getting Metrorail there. I was trashed by some regular forum readers with this suggested routing, but I feel great that TGV agrees with me that it is a valid corridor, Whichever corridor TGV eventually chooses would be great for Austin. Of course, Austin has much more room for a HSR train station at the airport, the old train station location downtown is being squeezed out by the Seaholm development.
Blue line basically follows the old MKT corridor and US 281 until closing onto the CBD, the Red line basically follows the old MP corridor and I-35.
The parent corporation of TGV was replying to a RFA/Amtrak issued RFI that didn't include any links to Houston. That's why any discussion of connecting Houston to this corridor was limited in this reply.
What I got from this reply was that the San Antonio to DFW HSR corridor was a viable project alone, without including Houston. No doubt, in my opinion, including Houston on future plans should only enhance the project.