Christchurch Rapid Transit: a Proposal for Rail

This post first appeared at TraNZport and is republished with permission.


Greater Christchurch is set to grow by 150,000 people over the next 30 years (to about 640,000 people based on recent projections). It’s important to note, however, that the area is currently growing by more than twice this rate, meaning it would not be beyond the realms of possibility that population growth over the next 30 years could be over 300,000, and could be looking at a projected population more along the lines of 800,000.

To deal with this growth, and address shortcomings in the existing public transport system, ECan approved the Canterbury Regional Public Transport Plan (RPTP) in late 2018, which, subject to new funding, provides for a near doubling of high frequency bus routes, introduces new cross-city bus routes in place of meandering suburban services, and proposes two rapid transit corridors – one north and one south-west – to act as a spine for the entire system and act as a catalyst for higher density developments.

The RPTP does not go much further than this, but does say that mode choice is not decided upon and could be rail (possibly referring to both light rail and commuter rail), bus rapid transit, or “trackless trams” (which I consider to be a form of bus rapid transit). These aspects are being looked at in the Future Public Transport Business Case, due to be presented whenever that happens.

The purpose of this post is to consider the three modes outlined above (commuter rail, light rail and bus rapid transit) and present what I think is a cost-effective approach to a first stage – or “start up” – rapid transit network that involves the utilisation of the rail corridors, combined with some bus rapid transit and an initial tranche of bus priority along the key corridors to the north and south-west. This network could then be incrementally upgraded and other modes considered in future stages to either compliment or succeed aspects of this proposal.

What are the rapid transit corridors?


Above is the diagrammatic map provided in the RPTP that shows the proposed new network, including the rapid transit corridors (orange lines). In general, they link the Christchurch CBD with key activity centres such as Papanui, Northwood, and Belfast in the north, Riccarton, Upper Riccarton, and Hornby in the southwest, then onward to the main growth nodes of Waimakariri and Selwyn respectively. These are the main, and most intensely developed corridors in Christchurch, linking the greater metropolitan area’s three component parts. It is where there is also greatest potential for transit oriented development.

There are, however, a couple of confusing aspects of this diagram worth commenting on. For example, the RPTP delineates corridors south to Hornby and north to Belfast, with dashed extensions to Rolleston and Kaiapoi respectively. Interestingly, beyond Kaiapoi there is no rapid transit route, but rather “lower frequency extensions to core routes” to Rangiora and Woodend. Apart from the fact that we don’t know what the dashed rapid transit lines mean, the situation with Rangiora and Woodend is odd in that Rangiora is a satellite town and regional centre of almost 20,000 people, and growing. The intentions of this are not clear. Another confusing aspect is the “dedicated corridor” only extending as far as Belfast and Hornby. Thinking about this in depth, I do have a sneaky suspicion that utilising the rail corridors is being ruled out at an early stage, which is a shame (hint: read on for more on that).

Thinking about mode choice

Roughly speaking, the corridors follow Riccarton Rd and Main South Rd to Hornby, and Papanui Rd and Main North Rd to Belfast. Bus rapid transit or light rail (or trackless trams – they are essentially the same thing), if it was to be a dedicated right of way as suggested, would require development of a new, segregated corridor. In line with bus rapid transit developments in Auckland, this would require property purchases and significant redevelopment of road space, and that can carry quite a hefty price tag (discussed in more detail below). The upshot is that the solution is more tailored to needs, but it comes at a price and with a lengthier timetable for implementation and, thus, outcomes.

Commuter rail would involve utilising the existing rail corridors currently used by freight trains, the occasional long-distance passenger train, and – once upon a time – commuter trains. The rail corridors don’t entirely follow the RPTP plans, and access to the CBD is limited, especially due to the situation at Addington Junction. These problems would have to be mitigated or rectified, and there are other potential costs associated with signalling, and installing passing loops and/or double track sections in addition to the expected costs of building stations and purchasing rolling stock. The upshot of commuter rail is it presents an opportunity to introduce rapid transit to more places in shorter time, and at far less cost, due to the corridor already being in place.

Understanding the value of each mode

First, we need better to understand what is sought to be achieved by implementing the rapid transit corridors (this is because the mode used could have an impact on the exact route taken). As far as I can ascertain from the Canterbury Regional Public Transport Plan 2018-2028 it is as follows:

  • to increase overall public transport patronage threefold by 2048
  • to spark higher density development and urban regeneration around key activity centres along the corridors.

Below is a high level assessment of the three modes. Each mode is measured against the a broad category identified as relating to the implementation of a first stage network (I promise this is highly scientific!):


Let’s now discuss in more detail as to how I came to the conclusions presented in this table, building on what I have discussed above:


In this instant, I consider that light rail and bus rapid transit would largely follow the designated corridors as desired, being either built within or near the existing roadway. Commuter rail, however, would use the rail corridors and, as detailed above, there are discrepancies between what is in the RPTP and where rail goes (though not by too much). The biggest issue is probably the lack of access into the CBD.


This is where there is a considerable advantage for heavy rail because the corridor is already there (largely). New light rail or bus rapid transit, on the other hand, would require significant works to create a dedicated right of way. For example, Auckland’s Eastern busway between Panmure and Botany, which has just begun construction, is costing $1.4 billion for an approximately 7km length corridor. The project requires property purchase, a new Panmure bridge for the busway, and a new road section to remove conflict between cars and buses at Pakuranga. Note that the distance from the current central bus interchange to Belfast alone is approximately 10 kilometres, whether via Cranford Street or Papanui Road.

It could be suggested that I have been a little harsh on my assessment of the costs of light rail, but have factored in the additional cost of laying rails, although the difference isn’t always as significant as is often made out (see below).


It’s also worth pointing out that Canberra recently introduced light rail along a 12 kilometre route for A$707 million and are planning a A$1.2-1.6 billion 11 kilometre extension. That is for considerably less per kilometre than Auckland’s busway, but has had the benefit of wide road medians to develop the corridor in, thereby reducing costs (not a feature of the designated RPTP corridors).


While it is possible to incrementally develop all three modes, from such a high level assessment it is really only rail that you could deliver a functioning network relatively easily, in a short space of time, and for low cost. Bus rapid transit could be incrementally upgraded from bus lanes and other lesser bus priority measures over the length of the corridor, for example, but it is debatable if that is actually rapid transit. Light rail, meanwhile, does not have such a luxury at all, unless it was considered as the end game of an initial bus rapid transit project.


Developing the rail corridor would allow greater flexibility in terms of disruptions to the transport network, economy, and people’s lives in general during construction. I talked about Auckland’s eastern busway above, and the work involved in developing that corridor should give an indication as to the kind of works light rail or bus rapid transit would require, and the impact that is going going to have through property purchases and road reconstruction.


Clearly, given the alignment with the corridors outlined in the RPTP, light rail and bus rapid transit should edge ahead by providing a single corridor where it is desired, although this comes at an up-front price. With mitigation work, however, commuter rail could still be reasonably effective.

Primarily, I would expect commuter rail to be more weighted to serving the satellite communities and the outer suburbs plus most key modes on the corridors other than Riccarton. However, questions could be raised about its contribution to spark higher density development along Papanui and Riccarton roads, although I think it would primarily affect the latter.

A solution should make best use of existing resources – presenting the proposal!

The proposal

So with all this in consideration, what do I propose as a “start-up” rapid transit network for Christchurch? The following is my take on how it could look utilising the rail corridors, and beginning the process of an upgrade of bus services along the RPTP routes to rapid transit. The first stage network would consist of:

  • a “Northern Line” (commuter rail) from Addington to Rangiora
  • a “Southern Line” (commuter rail) from Rolleston to Moorhouse Ave
  • a “City Line” (bus rapid transit) from Riccarton to Moorhouse Ave via the Central Bus Interchange
  • bus priority upgrades along Papanui/Main North and Riccarton Main South roads.



Although speculative, my proposal would be for an all day service on the two railway lines of 30 minutes, much like the existing Blue and Yellow line bus services, with more frequent services at peak (Approximately 20 minutes). This would require investment in passing loops/double tracking, and possibly signalling, particularly for the Northern Line. However, implementation could be phased, if desired, with an initial focus on peak-hour services, so as to ascertain demand before further investments are made (note: the 2014 ECan report found that peak hour services are possible with minimal investment – take a look at this excellent post at Talking Transport for more information). Personally, I am somewhat against that, as I think it should be done right first time, but as long as the bus rapid transit component (City Line) is in place, it should function.

Infrastructure and rolling stock

My view is that, initially, infrastructure would be simple. Basic platforms with shelter, and utilising as much existing infrastructure as possible. I’ve kept stations to a minimum to avoid cost and maintain faster running times. Again, the 2014 ECan report said it was possible for a 30 minute travel time between Rangiora and Addington, competitive with car and much faster than the bus, so a 20-25 minute travel time for Rolleston to  Moorhouse Ave should be possible.

In terms of rolling stock, much talk has been made of the fact that some of Auckland’s former diesel-hauled trains are still lying around, but these are being snapped up pretty quickly by KiwiRail, a tourist operation, and the new Hamilton commuter train service, so I think a more holistic approach to rolling stock could be taken, perhaps looking at newer rolling stock that might be suitable long-term. One thing to note is that in the near future the diesel multiple units that operate the Pukekohe shuttle in Auckland are due to be replaced when electrification is extended, and may be available for purchase.

The Auckland to Hamilton start-up commuter rail service will utilise modified ex-Auckland diesel metro trains.

Counting the costs

The network would be a balance between investing to ensure it is effective and utilising as much of the asset base as possible to keep costs down. In this regard, I think it is important to make the rail network work without too much capital investment, hence the proposed northern line terminating at Addington, and the City Line acting as the link to the CBD as a (much) cheaper alternative than extending rail into the city. It is also important to note that this is likely to be much cheaper than building a light rail or bus rapid transit corridor from scratch along both corridors.

The Government has offered $100 million towards commuter rail from Rolleston to Christchurch; with matching contributions from local government, and perhaps a business case for further funding to include the line to Rangiora and the bus rapid transit line into the CBD, that might be enough to develop this initial system. At a high level, I think that it would be looking at around $300-400 million for this proposal.

This would be a “first stage” with subsequent stages developing the network further. It should be noted that this does not preclude any of the following in future:

  • Introducing light rail or bus rapid transit along Papanui or Riccarton roads
  • Considering other modes in future
  • Expanding this proposal beyond its  current constraints by building new sections when and if needed/desired
  • Developing other rapid transit routes, when required, along other corridors in the future.

A case for commuter rail 

New Zealand is a country with low political capital for major public transport projects, and Christchurch, as the most car dependent of the three major centres, is no exception. While this is changing, particularly in Auckland, it remains that projects such as the development of rapid transit in Christchurch is going to fight a significant kickback.  Utilising the existing rail corridors to achieve an affordable start-up for a rapid transit network in Christchurch presents an opportunity that is sorely being ignored. It is simply an opportunity too good to give up on.

Image result for ottawa o train
Ottawa’s O-Train network began with a basic, affordable, diesel hauled pilot commuter rail service. Why couldn’t Christchurch do something similar?

There is an additional element to this, and that is the way Christchurch is developing now and in future. Historically, Christchurch grew up around a radial network of roads and tram lines, it didn’t grow along the railways (which is rather odd for a city that was an early, and enthusiastic, adopter of rail) Until the 1990s, Christchurch grew in a circle of roughly 10 kilometres in diameter, which means that, despite having a reputation for urban sprawl, the city was contained in a reasonably small area. Commuter rail was hampered by the fact it didn’t serve much of this area, and where it did serve, trams and buses were able to provide more direct services over shorter distances. This left it with the outer areas, which weren’t heavily populated and had limited demand for commuter traffic. This is exactly why Christchurch’s few commuter rail services were abandoned in the 1970s.

However, since the 1990s, things have changed dramatically. Christchurch is growing increasingly to the north and south-west, and satellite centres like Rangiora and Rolleston are now small cities in their own right. This growth is expected to continue, and you can read this brilliant post to understand more about the changing dynamics of greater Christchurch’s growth patterns.

Finally, sounding like a broken record, I would say that the greatest consideration really comes down to cost. As I alluded to above, I see commuter rail and light rail/bus rapid transit potentially performing two slightly different, though integrated, functions; the former to serve satellite areas and provide an “express” type service in the city, the latter to serve the inner and outer suburbs with more stops along the routes as outlined in the RPTP. Developing commuter rail now, and a first stage bus rapid transit line, is a way to get started on this in the more immediate future, affordably and effectively, while still retaining flexibility for future stages.

Christchurch once had commuter rail – is it the right time to use these lines again for passenger movement?


At the end of the day, I don’t particularly favour one approach over another when it comes to mode. I would even support a “trackless tram”, provided it was properly demonstrated, including from a long-term strategic view, to be the ideal solution. My assessment of the different modes is based on the current environment, including there being limited funding and political capital to invest in purpose built rapid transit corridors with dedicated right-of-way.

For whatever reason, local authorities have been reluctant to look too hard into the benefits of utilising the rail corridors, at least with traditional commuter rail. I find this a rather worrying aspect of discussion around rapid transit in Christchurch, and ask the question whether Auckland would have made the progress it has without first investing in its own commuter rail services. I may be at risk of being accused of promoting one particular mode for ideological reasons, but I fear that this is exactly what is happening within greater Christchurch local authorities. Talking about “trackless trams” but ignoring a dedicated right-of-way corridor that sits latent much of the day and could have significant potential to move thousands of commuters at a  fraction of the cost, seems pretty cracked up to me.

This proposal need only form the basis of an option that should be considered alongside other considerations. A commuter rail line from Rangiora to Addington, and Rolleston to Moorhouse Ave, integrated with bus services benefiting from increased bus priority measures, is undoubtedly a reasonable consideration for the establishment of a rapid transit network in Christchurch. it correlates with the outcomes of the RPTP, but provides a pathway that is more immediate and cost-effective. It’s there, so why not actually look at how to could be used and save money? My concern is that, once again, the situation could end up being “bus rapid transit” makes the most sense because the intention is not true rapid transit but a diluted form that doesn’t really fit the definition or result in the desired outcomes. It seems to me that removing commuter rail from the equation allows this scenario to play out, which in a city whose public transport is chronically underfunded and low quality, would be a damn shame.

The RPTP says that innovation is a key priority, but to make this a reality then the term “innovation” must mean more than simply relying on new technologies as silver bullets. It must also look to how to smartly utilise existing assets and resources in cost-effective ways, that best gains the outcomes desired, and fits the long-term strategic outlook.

3 thoughts on “Christchurch Rapid Transit: a Proposal for Rail

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