For 1), isn't most high speed rail in the world standard gauge (1.435 meter width)? That's also what most of North America uses, though existing tracks are prob

For 1), isn't most high speed rail in the world standard gauge (1.435 meter width)? That's also what most of North America uses, though existing tracks are probably not up to spec for high speed in other regards, such as 'smoothness', or turn radius and banking.