The recent state budget allocated $2.5 billion over 4 years for work on the Northwest Rail Link, including $314 million for the current 2011-12 year (mostly for land acquisitions). This will allow preliminary drilling along the proposed alignment, which will determine how and where the underground tunnels will be constructed. The project is still a number of years away from commencement of actual construction (the government is aiming to start on this by the end of 2015), with the final alignment and even the number/location of stations not yet finalised. Geotechnical work like this was done for the Parramatta to Epping Rail Line, Bondi Beach Extension, Northwest Metro, CBD Metro and Western Express, all of which were subsequently deferred (i.e. cancelled). So this is still not an indication that it’s definitely going to happen.
Technically, the final cost estimate has not even been come to yet. And based on previous experience with Sydney’s non-road transport projects, the amount is likely to only get bigger and bigger. In fact, it’s already happened. The Northwest Rail Link was costed at a very reasonable $360 million in 1998, blowing out to $6.7 billion in 2010 and most recently $8 billion in 2011. The 1998 figure was only for Epping to Castle Hill, which is one third the length and has a quarter of the stations of the current proposal, but was also entirely underground (whereas one third of the current route, between Norwest and Cudgegong Road, is above ground). It is also in 1998 dollars and should take inflation into account. But even factoring these things in, based on the 1998 cost estimate, the Northwest Rail Link should have a price tag of around $1.5 billion, not $8 billion.