Assessing alternatives to the CRL

With Auckland Transport announcing yesterday that they have selected a preferred route for the City Rail Link, this might be a good time to highlight some work that various bloggers on this site have been doing to build up a top quality repository for information on this project. In particular, this post shows what’s in the “Alternatives to CRL” page, which focuses not only on different alignments for the project but also on what other transport options exist to help achieve what the CRL looks to achieve – and how effective (or otherwise) those alternatives would be. Because of that, this is not really my blog post (only this introduction), but rather draws from the knowledge of all bloggers on this site, as well as our former admin as much of the page has taken snippets from past posts.

The Process of Assessing Alternatives:

One of the things which often comes up in analysis of the City Rail Link project is whether there’s a better/cheaper/quicker alternative which we should be investigating further instead of pursuing with the CRL in its currently proposed form. This is a very valid issue, as sound transport planning requires a thorough and robust assessment of alternatives to make sure we’re spending a very significant sum of money on the right thing.

Various elements make up a robust assessment of alternatives:

• Is heavy rail the right technology/mode, or should we be looking at something else? (light-rail, busway, on-street buses, monorail etc.)
•  Should the project be above ground, under-ground or at grade?
• What alternative alignments are there?
• How many stations should there be and what alternative station locations are there?
• Is the “do nothing/minimum” a feasible option? For how long?
• Are there a number of smaller/cheaper projects that could delay the need for a really big/expensive project?

Broad Alternative Assessment:

Before we get down to analysing the ‘short-list’ of genuine possible alternatives to the CRL, it is worth noting that a longer list of broad options have been looked at in the past. The project has a very long history, beginning at least as far back as the 1920s [history page will elaborate on this in the future], but the current push for completion began around a decade ago – leading to a 2004 study that looked at a number of different routes, building on earlier work which had analysed light-rail alternatives before preferring the “westwards extension of Britomart”.

The preferred alignment in the 2004 study is relatively similar to the currently preferred option – although without the deviation to Newton Station we have now: The red lines indicate alternative alignments that were looked at.

More recently, the 2010 Business Case included a whole paper dedicated to alternatives analysis. The paper goes right back to first principles in looking at options such as increasing road capacity, building a CRL but with fewer (or no) stations, relying solely on ferries, cycling, walking or buses, different bus options and so on. Here’s a brief look at the ‘longer list’ of options that were considered:
The business case identified four options worth exploring further:

• On-street bus solution
• Bus tunnel
• Expanded Britomart station
• City Rail Link

In more recent times we have seen other options thrown into the mix. For example, an overhead option was suggested by the Greenways Project. Most of the alternatives have fundamental problems with them, such as the overheard option being too steep for conventional heavy rail.

This page is going to look in more detail at the three most viable alternatives to the City Rail Link project: an on-street bus solution, a bus tunnel and an expanded Britomart station.

On-street bus solution:

Without the CRL in place, the number of passengers needing to catch the bus into Auckland’s city centre will significantly increase over time. The diagram below shows this trend, in the scenario of there being no CRL and bus capacity in the city centre being unconstrained (which obviously it isn’t):

The exact numbers are obviously just a guess, but what’s important is the clear trend: we’re going to need to deal with around a doubling of bus passengers by 2041 heading into the city centre if we don’t build the CRL. An ironic result of that is likely to be significantly fewer cars being able to get into town because many of the streets will have to be given over to being for buses only – to accommodate such higher numbers.

So how might the city centre handle such a large number of buses? The thinking about where buses should go in the city centre has evolved a lot in the last couple of years, but the CRL’s original assessment of alternative makes some sensible suggestions which are still valid – and give us some idea of the huge number of buses the city centre would need to handle:

It’s important to point out, obviously, that the CRL does not reduce the need for North Shore buses. However, by significantly reducing the number of buses from Great North Road and from Symonds Street/Central Connector, buses from the North Shore will not conflict with those other buses and have a lot more city centre streetspace available for them.

Given that standard bus lanes can only handle around 100 buses per hour, what kind of infrastructure upgrades will be necessary in the event we don’t build the City Rail Link? The alternative assessment highlighted a few things that might be necessary:

• Completion of the Waitemata Harbour Crossing project to establish bus lanes on Auckland Harbour Bridge (both directions), along with a structure to allow buses to access the Northern Busway via an Onewa flyover and bus lanes on the SH1 off-ramp to Cook Street; two-way operation of Cook Street as well as a new on-ramp from Cook Street westbound to the SH1 ramp. (Arguably this project is independent of the CRL although its need would probably be higher in the event CRL isn’t built).
• A 350m tunnel (approx) from Cook street beneath Nelson and Hobson Streets to overcome grade and intersection constraints
• Bus rapid transit corridors, station and grade-separated junctions. These are assumed to require property acquisition along their length to achieve additional corridor width.
• Reconfiguration of Britomart Bus Station to concentrate passenger activities in Queen Elizabeth Square
• Bus lanes on Mayoral Drive and Cook Street in both directions
• Wellesley Street converted to Bus Only between Symonds Street and Nelson Street
• Bus lanes required on Nelson and Hobson Streets between Cook and Wellesley
• A new surface bus station in Civic on Mayoral Drive and Queen Street
• Additional buses and bus operational costs associated with an average 88% increase in buses operating to the CBD

Aside from the cost and disruption of constructing this infrastructure, the impact of it all on the urban quality of the city centre would be immense. Wider streets, reduced general access, big bus stations in a number of areas, a whole pile more buses  and so forth does not seem like a very pedestrian friendly environment.

Along with other possible ‘on street bus solutions’ it is the impact on the quality of the urban environment which makes such options a non-starter.

Bus Tunnel:

Perhaps a more realistic alternative than on-street buses is the idea of a full-scale bus tunnel travelling across the city centre. This tunnel would link with the Northern Busway in the north and then into Upper Symonds Street at its southern end.

The bus tunnel itself can accommodate extremely high frequencies of buses along its route – as long as sufficient space is provided at the various stations for buses to pick up and drop off passengers. The assessment of alternatives noted that upwards of 500 buses per hour could be accommodated, although some buses would still need to travel on the surface streets (like with the CRL). Because of a need for shoulders and fire exits, the width of the bus tunnel would probably be greater than that required for the CRL – which obviously has some cost implications. The width requirement is detailed in the alternative assessment:

A two-lane CBD bus tunnel would have ample capacity to accommodate the expected up to 534 bus movements per hour (two directions) assuming no crashes or breakdowns. The capacity constraint for the bus tunnel would be the operation of the bus stations as well as the level of traffic congestion on the shared road corridors beyond the tunnel. Efficient operation of the bus stations would be critical and would require active management of bus and pedestrian movements. Bus stations of this type are proven technology in New Zealand, though operating costs are high.

However a bus tunnel of this length would require safe exits in the case of fire, necessitating fire-proof separation. Each separate direction would then need to allow passing in the case of breakdowns, so would probably need to be two lanes, implying two by two-lane tunnels.

This leads to the following cost comparison between the CRL and the bus tunnel alternative: So the bus tunnel is more expensive to build. But even that doesn’t truly highlight the real problem with this alternative. That is more about how it interacts with the existing transport network – especially at its southern end where 500 or so buses per hour are disgorged onto a number of local roads: requiring some pretty serious pieces of infrastructure for this all to make sense. Necessary supporting bus priority infrastructure for the tunnel are shown in the diagram below:The purple lines aren’t much of a problem as under all scenarios in the future we’re going to need high quality bus lanes along these roads (we already have them in a few places). The issue is more with the blue lines – which show the need for full busway standard priority along extensive portions of New North Road, Khyber Pass Road and Great South Road. As well as being expensive, disruptive and politically difficult to build, the really stupid thing about the necessary busways is that they duplicate the rail corridor. When you have a piece of high quality rapid transit infrastructure (the existing railway lines) it seems to make a lot more sense to squeeze the most you can out of them rather than building completely new duplicative pieces of rapid transit infrastructure right next to them.

And it is for that fundamental reason, along with the higher cost of construction compared to the CRL, the bus tunnel alternative doesn’t make sense.

Expanded Britomart Station:

The final serious alternative to the City Rail Link relates to finding ways to expand the capacity of Britomart station by means other than making it a through station and linking up with the western line at Mt Eden. There are a few ways this could be done. Back in 2010 Nick explained one way: by constructing what would effectively be another mini-station and feeding tunnel underneath Quay Street. This new station could eventually link into the CRL, but in the meanwhile the extra platforms and extra tracks into this newly expanded Britomart would probably buy some time before the station reached full capacity – thereby delaying the need for the project:

Nick has said that this idea is more about looking at the best long-term rail solution rather than finding a way to avoid the need for the CRL – as obviously just building the new platforms and the tunnel under Quay Street doesn’t do three critical things that the CRL does:

• Improve rail access to more of the city centre through the construction of new stations
• Significantly reduce travel times from the Western Line to the city centre as trains no longer need to travel via Newmarket
• Remove/reduce conflicting train movements at Newmarket, which themselves are a constraint on the capacity of the rail network

Another plan for expanding Britomart’s capacity was looked at in the assessment of alternatives that accompanied the original business case – which involved building a third line between Newmarket and Britomart. This option obviously involves some pretty serious infrastructure requirements (extra tunnels and bridges) and the widening of the tunnel into Britomart, which is generally understood to be near impossible due to buildings being constructed in very close proximity to it. And once again, even if possible, simply increasing the track capacity into Britomart does not solve the other three main goals of the CRL. The difficulty of widening the Britomart trench/tunnel as well as this option not achieving many of the things the CRL does achieve (as noted above) make this option not really worth it.

The “do nothing” option:

In any good assessment of alternatives, it’s always important to consider the “do nothing” or “do minimum” option. In some respects this option might be similar to the surface bus routes above, but without the necessary infrastructure constructed or the necessary bus lanes set aside, for that option to really work. What we are likely to see in the “do nothing” scenario is the stagnation of Auckland’s city centre as it becomes increasingly difficult to access, and an increasingly unattractive place to live, work or visit.

Employment will be pushed elsewhere in the region – meaning far less productivity as agglomeration benefits will be foregone. With fewer people wanting to live in the city centre (due to its congested and polluted nature) that will put more pressure on either other suburbs having to intensify or will see more urban sprawl happening.

Efforts to improve the city centre’s pedestrian focus will be in vain – with the streets needing to be used by buses and cars so much it simply won’t be possible to free up space for wider footpaths, linear parks, shared spaces and all the other fantastic ideas put forward in the Council’s City Centre Master Plan.

And the trains will become increasingly crowded, yet operated in an inefficient way because of this one big bottleneck on the system. We’ll have railway lines capacity of handling a train every minute or two only utilised to around 10% of their capacity – while our roading network gets overloaded.

None of this sounds acceptable at all – why is why the do nothing option really isn’t an option either.

The City Rail Link:

At the end of the day, almost by way of a process of elimination, the CRL really is the only viable, feasible and attractive option out of all the above. Yes it’s an expensive project, but as this page shows there isn’t a cheaper and easier option out there which provides the same benefits (or even close to it).

Read about the benefits of the City Rail Link

Return to main City Rail Link page 

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