Thoughts on Brisbane Metro

Summary: Brisbane’s busway network is a victim of its own success. The “Metro” project, while misleadingly named, is what’s possible as an incremental upgrade.

How did we get here?

Brisbane’s main surface-level transport corridors were mostly established by the middle of the 20th century. Queensland Rail train lines covered some parts of the city, while Brisbane City Council trams (generally running in the centre of the road, mixed-traffic) covered much of the rest. In the 1960s, the trams were replaced with buses,¹ many of which run the same routes today. In the early 1970s, the SE Freeway (M3) route was developed with the Captain Cook Bridge opening to traffic in 1973.

The 1997 Integrated Regional Transport Plan proposed busways (with grades suitable for light rail) along the SE Freeway to the Logan Hyperdome, to Capalaba via Carindale and Old Cleveland Rd, and to Carseldine via Chermside and Gympie Rd. These areas of the city are not served by QR heavy rail, and so were/are in need of a dedicated public transport right-of-way.

The Brisbane busway operational concept is an “open network”: buses collect passengers on suburban roads, then enter the busway for a quicker trip to the city without passengers needing to transfer. Busways were seen as a good incremental solution because sections could be staged as needed or where possible.

The first part of the busway, from South Brisbane to Woolloongabba, was delivered in 2000. In 2023, the busways extend south to Rochedale, east to Langlands Park (with “transitway” part time bus lanes being added further east), north to Windsor (with a non-contiguous busway tunnel under Lutwyche and more transitway being added to Chermside). Extension further south to the Hyperdome is about to happen alongside motorway works.

It’s important to note that building the sort of dedicated right-of-way, grade-separated busway Brisbane has is not cheaper than rail-based options. What a busway does permit is deferring capital investment on sections which would need to be there from the beginning for a rail-based option, possibly at prohibitive expense.

Not in the IRTP — but very successful — is the western half of the “Eastern Busway” to UQ Lakes, which has greatly improved access² to the University of Queensland from the other side of the Brisbane River. UQ is now the second-largest PT destination after the CBD itself.

For more detail, see Tanko & Burke 2013, “How did Brisbane Get Its Busways?”

What’s the problem?

The inner part of the busway from Mater Hill to the city became very congested by the 2010s. The most visible trouble points are Mater Hill in afternoon peak (as that station has short platforms) and queuing across Victoria Bridge³ and the Grey St intersection in either peak.

What’s the solution space?

Reverse branching

Many all-day trunk “BUZ”⁴ routes (which, in the south and east of the city, run via Mater Hill) have peak-only express counterparts (“Rockets”) which run to the city via the Captain Cook Bridge. This diverts CBD patronage away from the most congested section of the SE Busway, between Mater Hill and the city. On those terms, it’s arguably a success.

The main negatives of reverse branching are of course the hit to network legibility and that frequency is cut in half for a major set of destinations. When you’re going to Mater Hill, South Bank or the Cultural Centre, the Rocket service is one that you have to remember not to catch, or at least transfer from.

Only about half of the 300-ish buses through the Woolloongabba junction in peak hour run via Mater Hill. This means the effective “stopping” capacity of the busway is probably at or below 120 buses per hour. Above that, it gets overly congested because there’s not enough platform space.

Light Rail

The busways were originally designed to have light rail laid on them. It’s not clear exactly when this approach was given up on but there are certainly parts of the busway today which wouldn’t support conversion.

A system where all the major corridors were light rail would almost definitely be better from a capacity and passenger-experience perspective than what we have today. The main problem with light rail is “getting there from here”. Conversion to light rail would of course require laying tracks on the busway (or perhaps in some places making new corridor) but that’s only the beginning.

Matching the passenger capacity of the stopping routes via Mater Hill is not that difficult in isolation. A Gold Coast size tram (the length of the platforms at Mater Hill!) running every two minutes should be sufficient. But full conversion would presumably mean replacing the reverse-branch expresses too; and “tram every minute” operation would surely push the limits of reliability. Lengthening Mater Hill station would allow for longer trams and would surely be worth the expense at some point.

That’s assuming tram-only operation. The busway platforms are designed to allow for several buses stopped at once, and for buses to drive around each other. A tram has to wait for the platform to clear. For this reason it seems likely that mixed-mode operation would have lower capacity than either mode running on its own.

The core of the busway system (especially at King George Square) has routes from all over the city, so upgrading any one corridor still involves mixed running in the core.

Because of the busway’s “open” operation, suburban stations are not currently designed⁵ to support trunk-and-feeder transfers. Substantial works would presumably be required to allow for more of that.

On corridors with the patronage to support, say, 10-minute tram service or higher⁶ it would of course be better to extend the tram lines, reducing the need for in-corridor bus-tram transfers.

Conclusion: It’s difficult to upgrade to Light Rail incrementally, because of the issues with running mixed-mode and the interconnectivity of the busway network.

“Brisbane Metro”: longer buses

Fundamentally, the “Metro” project is about running longer bi-articulated buses. This is an incremental improvement: there are more passengers per vehicle, but the vehicles can still “play by bus rules” in terms of operational flexibility.

The two initial Metro routes will directly upgrade two existing busway routes: the 111 between Eight Mile Plains & Roma St stations, and the 66 between UQ Lakes and RBWH stations.

There will be some very limited network reform where minor bus routes are terminated at suburban busway stations (probably under 20 buses/hour in peak through Mater Hill). It also gives political support to other (though still largely cost-neutral) network reform which puts several⁷ all-day not-quite-a-BUZ routes on the Captain Cook Bridge. Finally, with new vehicles for the upgraded routes, their existing vehicles (which are often themselves articulated) can be deployed elsewhere.

The Lord Mayor has also expressed intent to expand the system so that it covers all the “busway” corridors. Since the vehicles are unlikely to be run in general traffic lanes (for several reasons), support for Metro expansion should also mean support for on-road Bus Rapid Transit lanes.

The project previously also proposed a major improvement at Cultural Centre with via-South-Bank buses getting to go under Grey St. This has been deferred indefinitely following disagreements between state and local government. However, taking cars off the Victoria Bridge has already allowed for intersection improvements at Grey St and the Melbourne St busway portal (i.e. fewer phases = more busway time).

I can’t seem to find project cost breakdown by specific elements but it seems likely the single most expensive element of the project is actually the Adelaide St tunnel. This largely replaces a very nasty turn between the Queen St and King George Square busway stations (including a one-way-at-a-time section!). It’s unclear whether the new tunnel could take a 43 metre tram as modelled above, but if it can’t then there’s surely no hope for the existing turn either!

Is it the best solution?

It’s not ideal, but it’s probably better than nothing. There’s a substantial question around whether it represents any kind of value for money and what the further upgrade paths are from here. Personally I think that the major civil works being done on this project would also be necessary for any sort of light rail upgrade, so in one sense they’ve been brought forward. The other alternative is to build a new parallel corridor, presumably as a light metro system similar to e.g. the Vancouver Skytrain, which would take over the core baseload demand.

But fundamental transformation has been quite deliberately avoided.

First published: 2023-08-10