An 'anagram' map of the London Underground (click for more). How's this? An anagram of 'Parliament' (a station in Melbourne's CBD) is 'Rampant Lie'. An anagram of 'Town Hall' (in Sydney) is 'Wont Hall'

The CEO of Melbourne Airport, Chris Woodruff, has a gripe. The Victorian Government is pressing ahead with construction of a $250 million rail line to support his competitor – Avalon Airport – but is spending a mere $6.5 million to study the warrant for rail to Melbourne Airport.

Yet as I noted once before, while both airports have enormous scope for expansion, Avalon is 55 km from the CBD and has just six scheduled flights a day. Melbourne Airport is 22 km away and is the second busiest airport in the country. It currently processes 28 million passengers a year, expected to rise to 40 million by 2020 – its annual growth is more than Avalon’s total annual patronage.

Mr Woodruff says Melbourne Airport needs a rail line because of traffic congestion at the terminal and on the freeway access roads. “We need rail”, he says, “sooner rather than later. A rail link has always been in the airport master plan. When the Government presses the green button on this one, we are ready to go.”

Cities without airport rail often think they need it. And yet as others have observed, the political popularity of airport rail “is always several orders of magnitude above its actual ridership”. Because there’s so much focus on airport rail in Melbourne, it provides an interesting case study to explore some of the issues.

There are a number of problems with a rail line that help explain the cautious approach of successive governments in Victoria. One is the cost. The Herald-Sun reckons an airport line from the CBD to Melbourne Airport would cost as much as $1 billion to construct, but I think they’re dreaming.

My admittedly rough and ready estimate based on current project costs is a lot higher. Assuming the same 20 minute travel time (off-peak) and ten minute frequency offered by the existing bus operator, SkyBus, I think a more realistic estimate of the cost of a service along the reservation set aside by the previous government would be in the order of $3 to $4 billion, maybe even $5 billion. Start thinking about a high-speed service and the cost could easily escalate to $10 billion or more.

There might be a lower cost option. If the proposed Melbourne Metro rail project goes ahead it would provide increased capacity to run more trains between the CBD and Sunshine. A new line could be run from Sunshine to the airport at a probable cost in the region of $1 to $2 billion.

Travel time would be closer to a still-reasonable 30 minutes but that’s the least of the issues. This option’s premised on funding being found for Melbourne Metro – the former government estimated the cost with 8 km of tunnel at circa $5 billion but I expect that’s too low by a considerable margin.

Capital cost isn’t the only consideration. The Victorian Government will also be wary of the poor initial financial performance of the airport train services in Sydney and Brisbane. As Sir Rod Eddington says, “Airport railway links are notoriously bad investments and there are plenty of examples of that around the world”.

The Government would also note that Melbourne Airport already has arguably the best public transport service in Australia. Buses have a 14% mode share, compared to 5% for Brisbane’s Airtrain and 10% for Sydney’s Airport Link. The main bus operator, SkyBus, operates at 10 minute frequencies for close to 24/7, whereas Airtrain offers 30 minute frequencies and ceases operation at 10pm (Sydney has a curfew).

The financial risks are minimal with SkyBus because it already covers its capital and operating costs and indeed contributes to the cost of improving the freeway. It also has considerable potential to add capacity, primarily by increasing frequencies. It’s not always as comfortable as a train and trips blow out to 40 minutes in the peak, but it’s effectively costing taxpayers nothing.

An airport train would improve peak period travel times and provide greater predictability for travellers going to the CBD (SkyBus can be affected by accidents and breakdowns on the freeway), but the Government knows it wouldn’t provide a permanent solution to the issue of traffic congestion on the freeway.

It also knows that, like SkyBus, a train wouldn’t do a lot for the majority of travellers. They’re not going to or from the CBD or to intervening stations, but to dispersed destinations across the metropolitan area. They’re still going to kiss ‘n ride, drive and park, or take a taxi (especially if they’re visitors), because it’s still likely to be faster and more convenient in the great majority of cases. If they’ve got baggage they’ll be even less likely to use the train.

Nor is the Ballieu Government likely to be persuaded by the fact there’re 12,000 jobs at the airport. That’s less than 1% of all jobs in Melbourne. Airport workers get concession fares on SkyBus and access to the 901 orbital SmartBus which runs at 15 minute frequencies for much of the day (and also connects to Broadmeadows station).

Public transport to the airport has deficiencies (particularly the location of the 901’s stop at the airport), but these could be addressed directly for a fraction of the cost and time involved in providing a train.

I don’t know if the Victorian Government gives a toss about greenhouse gases, but if it does it’ll note that a train to Melbourne Airport would be one of the most expensive ways of mitigating carbon imaginable.

There’s a lot of public concern about the high cost of parking at Melbourne Airport, but the Government will know a train wont solve that problem. It’s caused by anti-competitive practices and they need to be addressed directly.

So what it comes down to is essentially this: a lot of travellers already use public transport between the CBD and the airport. The question is: how much is it worth spending to reduce the travel times and improve the predictability of public transport trips made between the CBD and airport, in peak periods? These are primarily business trips and I expect the majority are made by visitors.

There’s a more important related question: are there other public transport projects (but it could be any other sort of project) which would provide a greater benefit from the funds than effectively replacing the existing bus service with an airport-CBD rail line?

Given the likely cost, I can’t see it’s worth constructing a rail line at this time. It very likely will be at some stage, but I think that’s sometime in the future. SkyBus might not be quite as pleasant as a train but it can be expanded and improved for a lot less than what a train would cost. I think there are other public transport projects that warrant funding ahead of this one.

So far as the Herald-Sun’s estimate of $1 billion is concerned, I suspect the Government would be very tempted to proceed with a new line if that’s all it cost. It needs to commit to something substantial in public transport before the next election (Avalon just doesn’t cut it) and, as the Herald-Sun’s survey shows, Melburnians would love airport rail. Trouble is, I reckon the cost would be much higher.

Cities don’t need rail lines to their airports, they need public transport! The form it takes isn’t usually the critical question. Rail isn’t necessary unless and until the volume of passengers makes it mandatory because other modes simply can’t cope. If there are lower cost options like buses that work, they should be used so that available (public) funding can be applied to other public transport projects that maximise benefits.