UK's geographical area is far smaller, but at least you have Eurostar.
Australia (with three east coast conurbations of c.5.1 million for Sydney and Melbourne, and around 3.1 million for Brisbane) lacks any. Cue constant, annoying airline delays.
Nor does Canada. In both nations, politicians refuse to fund and build true HSR. They prefer to spend their time away from the hoi polloi in special airline lounges such as in Oz the Qantas Chairman's Club.
Canada's Toronto - Quebec City 'fast trains' proposal appears limited to a maximum speed of 200kmh; in Australia, 160kmh is current max speed but only on portions of routes in NSW, Queensland and Victoria, and one line in Western Australia. South Australia and the small island state of Tasmania don't even have any local rural passenger trains!
Yorkie, count your blessings that you, your countrymen and visitors can use Eurostar, and otherwise trains operating at up to 225 kilometres an hour (missing from Oz and Canada).