Sydney Lessons
With the Southern Airport Line (Airport to Manukau via Puhinui Station) committed as a bus-way by both Labour and National I wonder if Sydney’s light rail scheme might offer us some lessons.
From the Sydney Morning Herald:
Why trams on Sydney’s booming inner west light rail aren’t running more often
Commuters wondering why trams aren’t running more frequently on Sydney’s inner west light rail line during peak hours despite a boom in passengers can now blame “capacity constraints”.
Internal government documents obtained by Fairfax Media show constraints such as “power supply, stabling facilities, single track near Dulwich Hill and fleet size” are limiting a significant increase in services on the line from Central Station to Dulwich Hill during the morning peak, when overcrowding is at its worst.
Sydney light rail fails to connect dots
Differing track standards on Sydney’s inner west light rail line and the south east line mean trams carrying passengers won’t be able to switch between the two.
Of an extra 95 weekly services announced last week by the state government, fewer than a third will run during the morning peak hours of 7am to 10am. The rest will operate during the “inter-peak” period of 10am to 3pm, and at weekends.
Patronage growth on the line from Central Station to Dulwich Hill has been “exceeding all expectations” of transport planners.
And it is set to accelerate over the next few years as thousands of new residents move into high-density apartment complexes along the light-rail corridor
…….
The Northern Airport Line (Airport to City Centre via Dominion Road) will face problems like Sydney is facing when the Dominion Road corridor intensifies as seen in Sydney. However, the Southern Airport Line could also face crowding issues if we do not get the mode right first time.
Traditionally we have over-estimated roads and underestimated transit projects. That is why you will find empty highways (toll roads have gone bust in Tauranga, Sydney and Brisbane) and overcrowded trains and busses.
Auckland is not immune with heavy rail and Northern Busway patronage continuing to surge and will do so even more once the City Rail Link is open in 2023. However, prior to that the Southern Airport Line will be open (around 2020) giving an express link from the City to the Airport via a transfer at Puhinui. When the Third and Fourth Mains come through the Southern Airport Line would be come the preferred route over the Northern Airport Line (see: City to Airport Express: 30 Minutes via the Southern Airport Line).

Source: Auckland Transport
That means will the bus way that makes up the Southern Airport Line be enough or should we go straight to Light Rail. Capacity on a bus is around 72-144 depending if single or double-decker while a light rail train can move 422 passengers. Given the Southern Airport Line would also run through the proposed Puhinui Gateway industrial complex on the way to the Airport the line would be popular with commuters as well as Airport passengers.
So I wonder for double the price of a bus-way and a ~4x jump in capacity going straight to Light Rail for the Southern Airport Line would be prudent. One other thing is that the Southern Airport Line can loop into the Northern Airport Line at the Airport giving a double connection.
Food for thought.

Source: The Spinoff