Elon Musk says first tunnel for proposed underground transportation network will open in December

[DetlefK]

5. European-style train-system won't work in the US bc US-cities are arranged differently.

European cities have a well-defined city-center: Go there and you can find every single important building just a short walk away.

Example: Cologne.
Get off the train and you are right in the tourist-quarter. The business-quarter, where all the big companies have their offices, is about 15 minutes by foot away, the university 30 minutes by foot. It's all very dense and concentrated.

US-cities are big, broad and dispersed. If you go to a US-city by train, you still need a car to get around. Unless you go all the way and give the city a good public transportation, this single high-speed train won't help.