Good evening, straight from Brazil. Well, I liked the route from Frankfurt to Cologne in Germany. This route would be great with the new ICE trains, namely ICE 3 BR407 and ICE 3 NEO BR408, both with signs for the high-speed lines of Brussels, Germany and the Netherlands. Still on the German routes, there could be more connections, such as from Frankfurt to Paris, Paris to Munich, etc.
In the case of the routes mentioned, the TGV and the ICE could be used, since both reach 320 km/h.
And still speaking of the Eurostar, the E320 operates in Belgium and the Netherlands. Both are connected by high-speed lines whose signs are different. Finally, I hope to get to know these routes on the TWS. And get to know the new trains!