The ATAP final report includes a 30 year vision for Auckland’s strategic public transport network. It is a substantial expansion of what we have today and quite closely resembles our “Congestion Free Network” developed in 2013:
ATAP generally goes out of its way to avoid making a call on the specific mode of new strategic public transport projects, instead using the phrase “mass transit”. However, it does show CRL as the only expansion of the heavy rail network (in red) with all other new strategic PT routes presumably being something other than heavy rail. Elsewhere, ATAP notes the need for ongoing investment in upgrading the existing heavy rail network over time to provide for growth in passenger and freight services – but not an “expansion” of that network.
This is quite a change from the 2012 Auckland Plan, which envisaged heavy rail to the Airport, the Avondale-Southdown Line and, in the longer term, rail to the North Shore. At times we have also seen the Mt Roskill rail spur being considered as another useful (if relatively small) expansion of the heavy rail network.
This change appears to have occurred on a relatively ad hoc project by project basis, rather than as part of an overall strategic plan, which I think sits behind much of the discomfort that people have felt about Auckland Transport decision to progress light-rail, rather than heavy rail, as their preferred strategic public transport mode to the Airport. It is worth thinking about this shift at a network level, in particular at the question of whether further expansion of the heavy rail network is likely. If not, it seems that CRL may actually be the end of the heavy rail network – rather than a key catalyst for its expansion.
Compared to other PT modes, heavy rail has some advantages and disadvantages:
- Very high capacity
- High speed
- Can leverage off existing network
- Very demanding geometry leading to high construction costs
- Creates severance when at surface level
For Airport rail, the capacity requirement of heavy rail wasn’t really a factor, due to relatively low projected passenger volumes – around 2,000 southbound trips in the morning peak in 2046 (compared to around 10,000 peak trips coming over the Harbour Bridge today in the morning peak):
While I think actual use will be much higher than this (models tend to substantially under-estimate future public transport use) it will still be well within the capacity capabilities of other modes like light rail. Therefore, the comparison really came down to a speed vs cost trade-off, with the high cost of serving heavy rail’s much more demanding geometry making this trade-off clearly fall in favour of light-rail.
The high costs of serving heavy rail’s demanding geometry means that heavy rail is most likely to “stack up” as the best option when we’re looking at a corridor with extremely high demand (i.e. beyond what might be able to be catered for through other modes) or where we can utilise the existing network.
North Shore rapid transit is potentially an example of a corridor which is likely to have very high demand in the future – because it is the only connection between a very large part of Auckland to the north, and the rest of the region. Early work a few years back suggested heavy rail as the preferred option, but more recently this appears to have shifted – illustrated by ATAP’s strategic PT network map linking North Shore rapid transit into the proposed Dominion Road LRT line. I know Auckland Transport are currently looking at different rapid transit options to serve the North Shore once the Northern Busway hits its capacity limits. I suspect the main question will be the trade-off between the extra capacity you get from heavy rail against the much higher costs of having to regrade the busway, along with the challenge of how it would link into the rest of the public transport system.
Importantly, even if the CRL does “complete” the heavy rail network and we don’t see major new lines in the future, there’s major upgrade of the network we have that will be required over time. Most obviously this is to separate passenger and freight services, but over time I see the need to separate local and express passenger trains – especially as the southern greenfield area grows. Therefore, ATAP’s $3 billion 30 year rail programme is almost certainly on the light-side of likely future investment in the heavy rail network in Auckland.