Overview
Melbourne Airport Rail is becoming a reality. Current plans have it opening in 2029, four years after Melbourne’s Metro Tunnel.
I won’t go into the project details here, but there are some concerns about them. The rail flyover at Albion and use of existing tracks from Metro Tunnel to Sunshine leave many questions unanswered. Other plans are on hold while Airport Rail is prioritised. We haven’t seen a viable business case, and I wonder if we ever will.
Here, I’m focusing on the future patronage of Airport Rail, and its effect on other ways of getting to and from the airport.
Through the busiest hour of the day, I predict airport trains will average about 220 passengers each to and from the Airport; less than half their seating capacity of 500.
This will be in 2029, provided air travel gets back onto a growth trajectory post-COVID. Airport Rail patronage might match, but not exceed, that of SkyBus. Together they’ll do little to stem the growth of airport-related road traffic, which will still have to cater for two-thirds of the demand.
However, even at this seemingly low level of usage, Melbourne Airport’s overall transit mode share will be very high by Australian – and even some international – standards.
Pre-pandemic:
- 70% of air travellers were interstate and international visitors, and two-thirds were on leisure trips
- 85% of air travellers were to/from Greater Melbourne, and over half were to/from inner Melbourne
- Airport area workers mostly lived close to the airport, and nearly all drove to work
- Transit took 20% of trips to and from the airport, mainly on SkyBus.
Amongst Australia’s main airports, transit already takes a high share of Melbourne Airport’s landside travel demand. That’s despite its being much further away from the CBD than most, and not having rail access.
My calculations suggest that Airport Rail could increase transit’s share of airport landside travel to over 40% after 10 years of operation, as long as air travel’s pre-COVID growth trajectory resumes (albeit with a few years’ lag).
That’s a significant shift, but it won’t be enough to halt absolute growth in car/taxi use. Traffic queues on the Tullamarine Freeway won’t be going away because of it.
Post-COVID, domestic air travel will probably bounce back strongly, but international air travel will take much longer to recover. However, there are some big unknowns:
- Will cheap, high-volume international air travel be possible, in a net-zero emissions world? I doubt that it’ll ever be as cheap as it was pre-COVID.
- Will high speed rail ever eventuate on the east coast? If so, it could take ten years’ worth of air travel growth away from Melbourne Airport.
Let’s delve into a bit more detail.
Pre-COVID airport travel
In 2019, when the Airport handled 37 million passengers a year, there were about 134,000 landside trips to and from the airport on an average weekday. 33,000 of these were airport area workers, leaving 101,000 trips to and from the airport for travel reasons daily.
The mode share of trips to and from the airport was as below. 20% of all trips were by bus, of which the vast majority were on SkyBus.
42% of all Airport weekday trips (57,000 trips) were to and from inner Melbourne, with mode shares as below. 31% of trips were by bus, but taxis carried the largest share (44%).
Trip distribution and growth
The maps below show the distribution of trips to and from the Airport, using data from a study I was involved in a few years ago, for airport passengers, and ABS journey to work data for airport area workers. The concentrations of air passengers to/from inner Melbourne, and airport area workers to/from places close to the airport, are clearly evident.
The maps also show my estimates of future changes, due to population growth and associated trip re-distribution. I’ve shown the amount of air travel activity as well (mmpa = million movements of passengers per annum): this might be a better indicator than the year, going forwards.
Despite strong growth in population in the west, outer east and north, these areas contribute small overall percentages to air travel. This is not surprising, given that 70% of air travel is from international and interstate visitors, and most of them travel to and from Inner Melbourne.
Time of day of travel
There’s a ‘lag and lead’ between the time of day that passengers arrive and leave by air and the time that they make their landside journeys, because of check-in, customs clearance and baggage collection times. Allowing for this (and adding movement of airport area workers) enables profiles of typical daily landside travel demand through the day. My estimates are shown in the graphs below.
Trips arriving at the airport in the mornings show a pronounced peak due to airport area workers arriving at the same time as peaks in both domestic and international air travellers. Trips leaving the airport are more spread out across the day, giving rise to a lower and broader peak in the afternoon.
The busiest hour (6-7am) sees about 6,300 trips to the airport, just under 5% of the daily two-way total.
The future for air travel is by no means certain
At the moment, post-COVID recovery is expected to add 3-4 years’ delay to pre-COVID population growth projections in Australia. On top of that, air travel will take longer to recover from the massive effect of COVID, and re-couple itself to that background growth. I think the overall effect could be to add 4-5 years to pre-COVID air travel growth projections.
However, a big unknown is how a global shift to zero emissions might change air travel in the longer term. If the world gets its act together on climate, will international air travel go down again? Will climate pricing put air travel out of our reach? Will high speed rail ever eventuate in Australia, providing an emissions-free alternative for intercity travel? These and other game-changers (including another pandemic, or severe climate deterioration if we don’t manage to prevent it) could have big implications for the future of air travel in the years following Airport Rail’s completion.
Effect of Airport Rail
I’ve built a simplified mode choice model to predict the effects of Airport Rail, accounting for its attractiveness as well as travel times, fares and service levels compared with those of other modes of transport.
Using this model, I predict that, soon after opening in 2029, if Melbourne Airport reaches 48 million air passenger movements a year, Airport Rail would attract similar patronage to bus. Overall transit mode share could increase to 33% (from 19% pre-COVID).
Ten years after opening, with continued air travel growth (to 69 million passenger movements), Airport Rail could exceed 50,000 trips a day, and bus a similar amount. Overall transit mode share could increase to 41%.
Airport Rail will attract patronage from car/taxi and SkyBus, as shown in the graph below.
Even with Airport Rail, growth in air travel activity means that car/taxi use could be 12% more than pre-COVID in 2029, and 37% more in 2039. Airport Rail won’t halt growth in car/taxi use, so queues on the Tullamarine Freeway will persist.
Of the 28,000 trips a day on Airport Rail in 2029, about 1,300 trips will be towards the airport in the airport peak-hour (6-7am). With the proposed 10-minute service, each train will carry about 220 passengers, at their busiest.
This isn’t much for a 1,380-passenger, 500-seat High-Capacity Metro Train. Airport trains will work harder than this on the Dandenong line; they’ll bring a lot more people into the city than they will to the Airport. Maybe there’s a case for a 15 or 20 minute service instead of 10 minutes, freeing up more trains to serve the rest of the Sunbury line instead.
We’ll have to wait until 2029 to see if my projection is right (and longer still, if air travel doesn’t pick up again by then), but it doesn’t seem like a big result for $10 billion of taxpayer funds. Incidentally, that’s about the same cost that the much more complex Metro Rail Tunnel was (in 2015 dollars), before the cost increases seen during its construction.
How does it work elsewhere?
Is it possible to gauge how Melbourne’s Airport Rail link might fare compared to other cities? Fortunately, there’s a reasonable amount of data available from other airports; I’ve assembled some of it below, from a few different sources.
Comparisons are odious; rail arrangements vary enormously from one city airport to the next, as do general public transport networks in their host cities.
The airports I’ve found data for aren’t a statistically reliable sample, and I can’t be sure that the travel metrics are defined consistently between them. Nonetheless I think they give some useful insights.
Firstly, I’ve compared airport transit mode shares (with and without rail) with overall city transit mode shares in the graph below. I’ve shown Melbourne as it was in 2009 (for comparison with the other cities) and 2019 (just before COVID), and as I predict it will be, with Airport Rail, in 2029 and 2039.
The graph shows a big spread around the linear trend.
Predictably, US and Australian cities are clustered in the low transit mode share range, European cities are in the middle and Asian cities are high (although my sample of them is small).
Airports without rail access are generally in cities with low overall transit shares, but they still mostly achieve higher transit mode shares than their host cities.
Adelaide, Perth and Brisbane airports all have transit mode shares lower than their city averages.
Brisbane is a special case worthy of further comment. Airtrain was privately built in the early 2000s and struggled to attract patronage initially. The operating agreement prevented the Government from sending any more transit to the airport; they built a new toll road instead, thus further disadvantaging Airtrain (Airport Link, the toll road, has also failed to achieve originally predicted revenues). Airtrain attracts only 8% of airport travel demand, in a city whose overall transit mode share is over 10%. The City of Brisbane now envisages that their new Metro transit system might serve the airport in future, after the Airtrain concession ends in 2036. I wonder if Airtrain will survive!
Melbourne is the only Australian city whose airport has an appreciably higher transit mode share than the city-wide average, although Sydney’s comes close (and its airport rail mode share has grown since 2009).
Amongst cities without airport rail, Melbourne’s airport achieved a high transit mode share pre-COVID. At 20% in 2019, it was nearly double the average for the city as a whole. This was mainly due to SkyBus, which had grown its share of airport travel considerably in the preceding years.
My predictions suggest Airport Rail would put Melbourne Airport outside the US/Australian ‘pack’ when it opens in 2029. Ten years after that, it would be much closer to European levels of airport (but not city-wide) transit shares.
If anything, this suggests that my predictions are on the high side. It would put Melbourne in a class of its own, where airport transit mode share is well over double the city-wide average.
Another way of looking at this is to compare transit mode share with airport passenger throughput, as below.
Although this isn’t a statistical sample of airports, it’s interesting that Melbourne is on the average trend line of the group. By 2019, thanks to SkyBus, it already had a higher transit mode share than Sydney and JFK New York apparently had in 2009, both similar in passenger throughput but also both served by rail.
When Airport Rail opens, my prediction of Melbourne’s transit share will approach that of similar-sized European airports, and by 2039 it’ll up there with London Heathrow and Paris Charles de Gaulle’s 2009 figures. This looks pretty optimistic, suggesting again that my forecasts, despite not filling up the trains much, could well be on the high side.
Conclusions
My prediction is that Airport Rail would attract about 28,000 trips a day when airport activity is at 48 million passengers a year. This could coincide with Airport Rail’s opening year of 2029, if air travel recovers from COVID’s effects.
This would be 16% of all trips to and from the airport. Added to SkyBus, overall transit mode share would be 33%, compared with about 20% pre-COVID.
At this level, there’d be about 1,300 passenger trips on trains to the airport in the busiest hour. This is 220 per train with the proposed 10-minute service, so airport trains would be running with less than half their seats occupied (there’d be plenty of room for luggage!).
Even with the proposed myki fare, Airport Rail would only match, rather than exceed, SkyBus patronage levels in future years. This is assuming that SkyBus will be upgraded to keep pace with demand growth as well, which would be the best way to increase overall transit mode share for airport trips.
Incidentally, shutting down SkyBus to get more patronage on Airport Rail would be a very bad move. Airport Rail won’t attract all Skybus users; most of them would probably choose taxi or rideshare services instead. I estimate that overall transit mode share would go down by as much as ten percentage points, compared to my predictions herein.
When (and if) the Suburban Rail Loop reaches the airport from the east, airport trains would then carry people on orbital journeys as well. Easy interchange would be required between SRL and airport trains at the Airport, to help attract people moving between the northern and western suburbs. I hope the station design will allow for this.
I’ve written this post to put my forecast on record. If a business case is published (without redactions!) we’ll see how my figures compare with Government predictions. It’ll be 8 years before we can see the actual result, and of course things could change dramatically again, at any time…
William McDougall 
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