The government’s announcement last week that they have launched a procurement process for light-rail suggests that things are going to move pretty fast over the coming months. One of the interesting parts of this process will be so see exactly what route the two proposed light-rail lines (City-Airport and Northwest) take. All the maps released in the past few weeks have been at a very conceptual level:
Looking at the ATAP document in a bit more detail, we get some clues about route alignment – but also a suggestion that further work will be done before some sections (particularly between Mt Roskill and the Airport) are locked in:
Auckland Transport and NZ Transport Agency board decisions in early 2017 confirmed the long-term mode for the Airport to City Corridor as light rail. Finalisation of exact timing, alignment and technical specifications will occur as design work progresses.
Investigation and design work on the Mt Roskill to City section of the route is the most advanced. Ongoing growth in public transport demand means this section of light rail should be progressed as quickly as possible.
Investigation and design for the Mt Roskill to Airport section is less advanced. The route is currently planned to follow State Highway 20 and State Highway 20A but is yet to be confirmed. It will be important for the next stages of investigation and planning to find the best balance between travel times, support for growth and urban development opportunities, and cost. Some sections of this route overlap with an existing rail designation, requiring careful design to ensure both forms of rail can be accommodated.
For the northwest there’s no particular discussion about the route, other than a mention that its delivery could be staged over time.
Of course, these projects have not emerged from nowhere and Auckland Transport has done a lot of detailed investigation into both corridors over the past few years. For the City to Airport corridor alone there has been a Strategic Assessment, a Programme Business Case (which was peer reviewed), a Bus Reference Case (informed by a Stage Timing Model), an Indicative Business Case and an Advanced Bus Study. All this work means that we have a reasonable idea of what the route between the city and the Airport might be:
ATAP suggests that the section between Wynyard Quarter and Mt Roskill is pretty locked in, but south of Mt Roskill there are a lot of options. These were considered as part of earlier business case work, although I wonder whether some elements of particular routes may have been hastily discarded in choosing Option 2 as the preferred route. For example, the section of the yellow route between Mangere Bridge and State Highway 20 in the map below may have merit, even if the alignment south of there would obviously be far too slow:
Within the Airport itself, the proposed alignment dips under the proposed northern runway (in the same tunnel as the road) before travelling along John Goulter Drive and Manu Tapu Drive before it ends literally right at the terminal (remembering that the Airport’s master plan proposes to integrate the international and domestic terminals into one).
Shifting to the northwest, we know a bit less about alignment details as obviously until recently most of the planning of this route was based on the assumption it would be a busway rather than light-rail. This change probably makes the most difference at the city end, with the light-rail corridor presumably going to link into the City-Airport route around Upper Queen Street. For the rest of the route, I imagine the there won’t be massive change, which generally means it will probably look similar to what was proposed for the busway:
Between Westgate and the City Centre there are really three main sections, and the proposal was quite different for each:
- A busway on the southern side of the motorway between Westgate and Te Atatu
- Bus shoulder lanes (which already exist, although with significant issues) between Te Atatu and Pt Chevalier
- A busway on the northern side of the motorway between Te Atatu and Newton Road
Bizarrely, Auckland Transport’s analysis effectively ended at Newton Road (which probably explains why they thought a busway would be OK) so it’s not clear at all what route buses would have taken from there into the city.
The move to light-rail will probably mean the most change for the causeway section, although in theory the space currently occupied by the bus shoulder lanes could be used by light rail (which may require all the motorway lanes to be jiggled around a bit, but no great drama). If the next steps of the project’s design keep the Westgate-Te Atatu section on a different side of the motorway to the City-Pt Chevalier section then the transition points will be an interesting engineering and design challenge.
Finally, I wonder whether the next phase of design will take another look at whether there are enough stations along the route, only having one station between Lincoln and Westgate seems a bit lean. Otherwise the stations look like they’re in fairly logical locations and could enable some great development opportunities along the route, particularly around Pt Chevalier/Unitec, Te Atatu, Lincoln Road and Western Springs (where the Council owned Chamberlain Park golf course sits right next to the planned station).
It will be fascinating to see more information emerge on this over the coming months.