There was a time in history, when Los Angeles was too far and isolated from Washington and NY to warrant a train line. The track linking Perth to Adelaide already exists. What might be needed is an extra track for freight and a speed train and some modifications to make it happen. Flying around Europe is also cheap even cheaper than flying around the east coast of Aust. but that doesn't stop Europe having and still improving its train system, same goes with China and many other parts of the world.
