If You Were Going To Add A Full High Speed Route In Tsw2 What One Would It Be?

You mean the 1970s Directline. Of these Trains only ETR1000 can layer onto French LGV Networks KVB VACMA TVM-430 while ETR610 can go on German routes like Frankfurt Am Main Mannheim Karlsruhe Basel route because of PZB Sifa LZB in addition to ETCS. Even a portion of Haputstrecke München Augsburg München Passing to Hbf section is used for ETR610 RAbe 503.