What would make a traveller choose a fast train between Melbourne and Sydney or Canberra and Sydney in preference to a jet?

Would it be the superior comfort and space for the cheapest rail seats that exceeds that of flying business class on a jet, never mind being squeezed into economy class?

Would it be the convenience of a faster overall trip time between whatever part of Melbourne or Sydney you set out from, and the place you visit in the other city?

Could it be the ability to work usefully and within more personal space on the 350kmh three hour trip to the other city using on board wi-fi?

Price may not be the factor here that many critics of high speed rail claim it to be if you are no longer paying airport parking fees in one city, or a set of costly taxi fares in the other, because their elimination will make any fare differential between the transport modes less significant.

And trip times at three hours by rail versus 90 minutes by air plus all the delays, security theatrics and general frustrations of using airports plus the distance of Melbourne Airport from-well-Melbourne, definitely conspire to put fast rail way ahead of jet airliners over such distances.

It is painfully true that considering fast rail versus air travel by these criteria may be fanciful in that Australia has never successfully managed to make its metropolitan rail systems work to world standards, or even to master stored value ticketing systems.

But there is a little more political will for high speed rail that before, even if the study everyone is quoting was funded by the financing and construction interests that would benefit from any fast rail project in Australia.

While we don’t have a disengaged and clinical examination of the real cost and consumer behaviour issues, the argument about rail investment, and in particular, its benefits for regional development, may be reaching a set of junction points that will either derail it, or put it on a faster track to realisation.

The current media reports about the fast rail report are facile. The notion that fast rail developments can remove the need for a second Sydney Airport in Sydney oversimplifies the issue.

If we assume that the fare to go from a high speed terminal in Sydney to a station at Canberra Airport in 50 minutes has to generate a commercial return, it is not going to be at prices of $15, $25 or $39, which are the quotes from Murray’s Coaches for a seat between both cities this week.

The 50 minute flight is also quoted this week as costing between $123-$446 on Qantas. The bus takes 3 hours 15 minutes to get between the Jolimont terminal in Canberra and Sydney International, and an extra 15 minutes to Central station.

So in terms of access to a remote Sydney airport, whether it be Canberra, or somewhere else, a coach is always going to bleed away some patronage from a high speed rail line, and some potential users may well drive directly from their homes to off-site parking at Sydney, which can be found for considerably less than the cost of parking at the airport.

At the moment, flying between Canberra and Sydney involves total trip times that would exceed that for private cars or a coach service for trips that end away from Sydney Airport, in its north-west and greater western reaches, where the expansion of economic activity creates a need for a second Sydney airport, now!

Even the use of flights between Canberra-Sydney for international connections seems to be of diminishing relevance because Canberra will itself get medium capacity wide body connections to Asia hubs and NZ cities in the shorter term, and Melbourne Airport is far more convenient for domestic-international links because of its integration of all flights in or right beside the main terminal.

Canberra does have a bright future as an alternative airport to Sydney for low cost international carriers delivering passengers onto connecting coaches to the harbour city that is unlikely to be influenced favourably by a much more expensive if faster rail link that is almost certain to require a further coach transfer at the Sydney end anyhow.

The complication for using a high speed rail link to a remote second Sydney Airport arises from additional time and costs to reach the Sydney end of the link, and the time and cost from there to the distant airport.

There is definitely a case for using high speed rail technology to advantage in Australia, if we can get the financial engineering rather than the physical engineering right, and there is a compelling case for a second Sydney airport in Sydney.

But if we weld these projects together there is also a danger that nothing will be done to achieve either as governments choke on the magnitude and complexity of such a combination.