It’s the one labelled ‘caps-lock’. Probably needs a key combo to actually toggle caps-lock.

Similarly the left ‘shift’ is also the ‘a’ key. I would guess tap for ‘a’, hold for ‘shift’.

This just seems like hand-wringing for the pitiful state of the rail system in the USA. A country can have many dense population centres separated by large distances, making HSR viable and worthwhile, but still have low population density overall - just like the USA. The only real obstacle is political will/public support.

Western China has around half the population density of the USA but is already served by a 1,900km HSR line.