I am still extremely sceptical of the need for Badgery's Creek, in relation to a HST BNE-SYD-CBR-MEL. My reasoning being that, even though a HSR link on this corridor is not, at the moment, commercially viable, if it was to eventuate it would reduce a huge number of aircraft movements from Sydney Airport (I will refer to it as YSSY, the ICAO code for it).
Assuming a reasonable system was built, I would expect a very significant reduction in aircraft movements from Sydney to points along the HSR route. But given traffic to other destinations and growth in that traffic, that just buys you a few decades of spare capacity.
Think of it this way, if a huge amount of money was spent on a HSR link BNE-SYD-CBR-MEL, when all the consortia want is "tax breaks" (in other words, not paying tax on income received, which I don't have a problem with, the tax revenue foregone would not be coming in anyway if the project DOESN'T go ahead) then it is revenue neutral to the Commonwealth, but might actually help the bottom line in terms of reduced unemployment (so less Centrelink payments) and increased GST income (due to now employed people spending more). So improving the bottom line for the Commonwealth.
I am not aware of any reasonable proposal from any consortia that suggests that they would build the complete HSR system if tax breaks were provided. Some sort of proposal like that existed for the Sydney to Canberra segment in the late 1990's, but we don't know any details, though it has been hinted that what was being asked for was very much a step too far.
What has been suggested is that if the government paid to build the system, then it would be viable for private operation.
Even if there was such a "tax break only" proposal, as above, the HSR system would very much likely take traffic off the current airlines. The activity associated with that airline travel provides tax revenue, loss of that activity then means you lose tax revenue. It is not neutral to the bottom line. Similarly, after the initial boost associated with construction (which you get with any local construction spend - including spend on airports...), you are not likely to see large changes in employment - new jobs in the HSR system will, to a rough approximation, just be matching jobs lost from the aviation system. How that actually plays out in detail depends on the relative labour efficiencies of rail travel versus air travel.
But experience around the world has shown that providing high-speed rail links vastly reduces the demand for air travel. Business travellers benefit by being able to work during the entire trip, something they can't do if they are flying, due to connectivity issues, as well as the time they spend with security and all of the rest of the garbage that is associated with flying. A journey time, by HSR, of under four hours, would be competitive with air travel, when looking at city centre to city centre. and HSR will provide this.
Yes, though with time I expect similar level of security to be in place for HSR travel as for airline travel, and "connectivity" is becoming less and less of an issue with time.
One issue with Sydney airport at the moment is peak period congestion. With an additional airport operating, that should be mitigated to some extent - reducing some of the delays currently experienced.
If the HSR was to go BNE-SYD-CBR=MEL, then most of the SYD-BNE, SYD-CBR, SYD-MEL and CBR-MEL air traffic would be eliminated, as would a large amount of SYD-originating regional flights. The number of movements at YSSY would be so reduced that Badgerys Creek would not be needed at all. So, instead of the Commonwealth spending a huge amount of money building Badgerys Creek, why not just forego some revenue - revenue which will not be received if the HSR doesn't go ahead (so no money lost) - and let the HSR go ahead - at no cost to the taxpayer (apart from foregone revenue, revenue which would not be forthcoming anyway if it doesn't go ahead) - and then avoid the cost of this airport?
[/quote]The need for Badgerys creek would be deferred, not eliminated. It has been a while since I looked at this, but estimates were presented in the Sydney basin capacity strategy, and also discussed to a limited extent in the phase two study. From memory it might be something like a twenty year deferral. That's not an insignificant deferral, but it is also about the same amount of time as it would probably take to build the entire HSR system.
The biggest issue with your argument though, is that the cost to government (state and federal), under reasonable proposals, of building the HSR system is something like $100 billion. The cost to government (state and federal), under reasonable proposals, of building Badgerys Creek is only perhaps a few billion - what is expected is that private enterprise will build, own and operate the airport at their own cost, government will just be paying for things like connecting infrastructure (maybe some road extensions, perhaps one day a train line). Even if the government ends up paying for everything associated with the airport, its total cost (when fully constructed in a few decades time) would be a mere fraction of the cost of the HSR system.
You are not "avoiding cost" by spending $100 billion in order to avoid perhaps $10 billion.