This is no silver bullet (train)

It would be nice to have, sure, but keep in mind a fully loaded HSR train could be equivalent to perhaps just 3 fully loaded aircraft. Europe's Eurostar HSR for example can carry 800 passengers, or the equivalent of two and half typical passenger jets. So given the dozens of flights each day that could be affected by closed airports, you would need a very large number of HSR services at a high frequency of service to provide a viable alternative. That's a big investment for a small number of days in a year.

How is the alternative funded?

Air travel is run by private companies. The airports are also privately owned and operated. The fares between major capital cities – the same destinations proposed by HSR – are very cost competitive. HSR would require not only the lines and stations and tunnels and bridges and the rolling stock and marshalling yards and signalling technology to be funded by the taxpayer, but the operating costs (ie the annual losses) would have to be massively subsidised for the trip fares to be remotely comparable to air travel.

Will HSR bring regional benefits?

It is hard to see how, unless there are multiple stops in regional centres. In which case it's not high speed, which defeats the purpose entirely. There are already intercity passenger rail services with multiple stops. They are hugely subsidised but still very few people use them.

But what about China? Haven't they recently built one?

Yes. It runs between Shanghai (population 26 million) and Beijing (population 22 million). Each city has a population roughly equal to the entire Australian population. Not only that but Chinese methods of funding, constructing and planning infrastructure could not be more different than ours. If some greenie in China miraculously found a rare frog whose only remaining habitat was on the proposed route, the greenie would be in jail. Nuff said.

But what about Japan? Or the UK?

Japan's Shinkasen first opened in 1964. It connects some of the world's biggest cities in one of the world's most densely populated countries and is operated by a notoriously efficient people. Could not be more dissimilar to Australia. The UK's HS2 project is already in strife, with allegations that MPs were misled about project costs and a budget that started at £34bn but which Treasury now thinks will be closer to £100bn.

But isn't the USA also building one?

They were but it's been halted due to massive budget overruns. Announced in 2008 but now dubbed "The Train to Nowhere without a Conductor" California's high speed rail was to connect LA (population 13 million) with San Francisco (population 4.8 million) over 1200 kilometres at an initial cost of $33 billion that was to be completed by next year (2020). The incomplete project is now estimated to cost $100 billion to complete and it can't be finished – even if the remaining funds are found – until 2033.

The new California Governor Gavin Newsom had to "bite the bullet" when he announced in February this year: "Let's be real. The current project, as planned, would cost too much and respectfully take too long. There's been too little oversight and not enough transparency. Right now, there simply isn't a path to get from Sacramento to San Diego, let alone from San Francisco to L.A. (Los Angeles). I wish there were."