Trips generated by Melbourne Airport air travellers are concentrated in the CBD and inner suburbs

The Committee for Melbourne held a seminar last week on the perennial idea of building a mass transit link between Melbourne Airport and the CBD. I was a panellist in the first session, which considered the question:

What is the problem we are trying to solve?

That’s an excellent way to think about the topic. I’ve previously argued we must look at access to the airport from all parts of Melbourne and Victoria, but I’ve no problem with focussing on a link to the CBD as it’s bound to be a primary component of any solution. After all, we know from previous studies that airport trips are heavily concentrated on the city centre and inner areas.

If a private investor wants to pay the full cost to build and operate a mass transit link, then I think the question answers itself. But there’s no sign that’s going to happen. The privately financed Sydney and Brisbane rail lines both struggled in their early years so it’s likely government will be called on to pay, in one way or another, the full cost of the link.

For the purposes of this discussion, I’m going to assume the solution is a heavy rail line. There are various route possibilities, although the leading contender must be the at-grade alignment via East Albion that was reserved some years ago. The likely cost, assuming an elevated station at the airport (like Brisbane’s), is circa $3 Billion. The Andrews Government favours connecting it with Melbourne Metro rather than terminating in the CBD at Southern Cross station.

That scale of expenditure demands a focused and precise understanding of why we should build it. There’s the inevitable danger the rationale gets clouded by populist appeals to non-central concerns. In my view, the immediate “problem” to be solved is to move travellers from the airport to the city centre. At present, that’s mostly done by taxis, private vehicles and SkyBus.

A rail line could be justified if one or more of the following conditions apply:

  • There is inadequate capacity to move passengers between the airport and the city centre
  • The travel time is unacceptably long
  • The travel time is excessively unpredictable or unreliable.

Of these, capacity is the key justification. That’s because SkyBus could be engineered to provide fast and reliable trips, at lower cost than building a rail line, if it were given dedicated road space as recommended by Infrastructure Victoria.

But while SkyBus could increase frequencies and the size of vehicles in order to carry more passengers, there’s a limit to this technology. There’ll inevitably come a time on the Airport’s current bullish passenger projections when buses will no longer cut it on such a busy route.

Infrastructure Victoria thinks a train won’t be required for at least 15 years. Perhaps, but demand changes so it might be sooner, or it might be later. It’s therefore pleasing the Commonwealth and Victorian governments are starting to plan for the possibility of a link.

There’s no shortage of other arguments thrown into the public arena to justify building a rail link. The main ones I hear most are:

  • It would reduce traffic congestion on the motorway network
  • It would moderate airport parking charges
  • It would be city-shaping infrastructure e.g. it would promote development of a more polycentric urban form.

I think these are secondary considerations that are in any event doubtful rationales for such an important investment.

The phenomenon of latent demand means a rail line won’t produce a sustained reduction in traffic congestion any more than building or widening a motorway will. Any road space liberated by motorists who divert to the train will eventually be taken by other motorists, most of whom aren’t going to the airport. The value of an airport train lies in providing a better alternative to driving, not in making travel by car easier. The way to deal with traffic congestion is to reduce demand for driving in the first place e.g. by road pricing.

Nor will a train have much impact on parking fees at the airport. The mode share of the train in Brisbane is just 7% and in Sydney it’s 17%; that still leaves a lot of travellers looking for a car park. High parking fees are mostly the result of monopoly pricing practices and should be addressed by regulation. Indeed, charges would increase significantly if airport parking were used as an indirect way to price road use.

The claimed city-shaping benefit of rail lines is uncertain. Transport systems have a generalised impact on land use at the metro level, but it’s much less assured at the level of specific lines or locations. There are a lot of stations in Melbourne that even after more than 100 years have virtually no development around them. Research shows transit doesn’t necessarily lead to the increases in land value, or the greater development, implied by grandiose “city-shaping” claims.

In any event, the two planned intermediate stops on the Albion route, Footscray and Sunshine, are already on rail junctions. Yet Footscray is only the eleventh largest activity centre in the suburbs and Sunshine the twenty sixth. Together, they account for circa 0.6% of all jobs in Melbourne. It’s worth thinking about how many firms would choose to locate in these centres, and thereby forego the agglomeration benefits of the massively larger city centre, just to gain a few minutes in airport travel time.

If the route took in large potential redevelopment sites at the former munitions site at Footscray and/or Essendon Airport, this would be a stronger argument, but by no means an assured one. There would be constraints on the number of dwellings that could be built on these sites and, in the case of Essendon, an alternative location – inevitably with lower aviation benefits – would need to be found for its airport function.

The longer route and/or tunnelling required if the line is to do “double duty” would add to the capital cost and/or increase total trip time. Both of these factors could weaken the Benefit-Cost ratio. Any increase in travel time due, say, to a longer route or more stops, makes the train less competitive relative to other modes and may weaken patronage. This is especially problematic as time saving is by far the dominant benefit in transport projects.

These sorts of issues, plus financing options like value-capture, have a place in assessing the case for airport rail but they’re secondary; they’re not the key reason why a rail line should be built. The benefits and costs associated with them are relevant but should be considered in subsequent phases when choices are made about options e.g. one route vs another.

The decision on if and when some form of mass transit link should be built (almost certainly rail), should turn on fundamental transport criteria like capacity, trip time, and trip predictability.

See other recent articles on the subject of airport mass transit links: