Will an airport rail link reduce GHGs?

Given the evident public interest in the idea of a rail link from the  CBD to the airport, I thought I’d look more closely at some of the key rationales for this project, starting with the claim that it would reduce greenhouse gas emissions.

Energy use and emissions (PTUA)

I’ve looked at this issue and, on my admittedly simple calculations, I conclude that the value of greenhouse gas (GHG) savings from a rail line is likely to be minor compared to the probable cost. There are far cheaper ways to offset equivalent emissions than building a rail line.

I looked at this by making the following simplifying assumptions.

First, I assume that a new rail line captures 20% of airport passenger traffic or five million of the current 25 million annual passenger movements at Melbourne Airport. This is double the share captured at either Sydney or Brisbane (around 10%), and almost three times the 7% estimated in feasibility studies.

Second, I assume that all of the current two million passengers using Skybus transfer to the new train (i.e. Skybus ceases to operate) and three million passengers transfer from cars, including taxis.

Third, I assume an average distance of 22 km from the CBD to the airport for bus and train. I assume that the combined average distance travelled to the airport by the cars and taxis that are replaced by train is 35 km. Read the rest of this entry »


Does a rail line to Melbourne airport make sense?

The Age ran a front page story on Saturday (Train derailed by buck-passing and vested interests) on the need for a rail link from the airport to the CBD. I say story, but as the headline and this quote indicate, it was more advocacy than news:

“But thanks to decades of buck-passing and pandering to vested interests by successive state and federal governments, Melbourne – unlike so many other cities of its size and wealth – does not have a railway line to its airport”.

So having pressed the civic pride button, it’s a pity The Age didn’t also push the rationality pedal and ask: is there a case for constructing a new public transport system (rail) to compete with the existing one (bus)?

Airtrain terminal Qld international airport

I would quite like to have a rail line from the CBD to the airport, but as I’ve indicated before (here and here), only if it makes sense. Let’s look at some pertinent issues.

First, the feasibility studies undertaken by the Government conclude that the numbers for rail don’t stack up (yet). The most recent evaluations, undertaken in 2001 by BAH and in 2009 by IMIS, both concluded there is not a strong enough case to build a new rail line to the airport.

The Department of Transport projected rail would capture only 9% of all airport trips and would require a subsidy of $350-450 million over 10 years (in 2001 dollars).

Second, in 2003 the Government upgraded the Skybus service so it could deal better with congested conditions around the CBD and on the Tullamarine Freeway. According to the Transport Department, new roadworks enabled Skybus to bypass traffic delays at the Tullamarine/Calder Freeway interchange and at the city fringe. The package included lane widening as well as line marking changes to create an emergency lane wide enough for buses. Read the rest of this entry »