I think term "Bullet train" only refers to the Japanese high speed train and is called such because of the shape. The new Amtrak
Acela is more like the TGV but without the dedicated trackage. It will be faster than the current Metroliners by about 30 mph. Acela will travel at speeds up to 150mph while TGV tops out at about 180mph. The main difference is the dedicated track. Thats also where the cost is! If it proves successful, then we will see the same trainset or variations in other locations in the US although at much slower speeds. Pacific Northwest corridor is getting Talgo style trains! We in the USA have just not put the money into track improvments that the Europeon and Japanese governments have.