The Third Main - Wiri to Quay Park

The rail line between Westfield and Wiri is the busiest part of Auckland’s (and New Zealand’s) rail network with 380 freight services and 1500 passenger services travelling through the area each week.

KiwiRail is building a third rail track alongside the two existing ones to ease congestion and provide faster train journeys and reduce delays.

What is a 'Third Main'?

Auckland’s rail network currently has two sets of tracks and operates like a two-lane road, with trains travelling in different directions on each track.  These tracks are call the ‘up main’, for trains heading   north and the ‘down main’ for trains heading south.   

The ‘third main’ is a third set of tracks that will act as a passing lane for trains through this busy part of Auckland.   

This upgrade will:

  • Allow for anticipated growth in both freight and passenger rail services ahead of the opening of the City Rail Link
  • Improve rail links to key freight hubs, including KiwiRail’s Westfield and Southdown freight terminals and the Ports of Auckland inland port at Wiri. 

Preparatory work began in late 2020 and the project will be completed ahead of the opening of the City Rail Link.

The New Zealand Government has allocated $315 million from the New Zealand Upgrade Programme for this important project. 

Once the Third Main Line is built, trains will use the new rail line from south of Wiri to north of the Westfield junction on the Eastern Line. There will also be new track connections so trains can move from one rail line to another.


Works are focused around three locations:

  • Westfield and Wiri junctions – Third Main and track reconfiguration 
  • Middlemore to Puhinui - Third Main
  • Quay Park - Track reconfiguration to allow for better freight train movements in and out of Ports of Auckland


Current status

Works are underway at Westfield and Wiri junctions and are expected to be completed by early 2022.

Work is expected to start on third rail track between Puhinui and Middlemore in late 2021.

The project in detail

Westfield Junction

This junction between the Eastern and Southern lines also provides access to KiwiRail’s Westfield and Southdown freight terminals where freight is loaded onto trains for transportation.

Improving the entry and exit points to the freight terminals and across the junctions will allow freight trains to move more efficiently and will mean slower moving freight trains won’t delay passenger trains.

Wiri Junction

At Wiri Junction trains travel to Ports of Auckland Inland Port, Auckland Transport’s EMU Depot (where electric trains are housed and maintained), the Manukau line and the Southern line.

The new additional line will mostly be used by freight services and will prevent these slower, longer trains from delaying faster passenger services by separating freight and passenger trains.

Middlemore to Puhinui

Constructing an additional rail line on the western side between Middlemore to Wiri will ease congestion by:

  • Reducing conflicts between freight and passenger services
  • Making room for more frequent freight and passenger services
  • Enabling express trains to pass stopping services

Works are expected to start in late 2021. Improvements will be made at Middlemore station. 

Puhinui and Papatoetoe stations are already able to accommodate the new rail line. 

At Middlemore Station a new platform and pedestrian overbridges will be built improving access and safety at the station.

Some areas of the rail corridor need to be widened to accommodate the new rail infrastructure. We are working with landowners along the western boundary of the corridor.


All works will be within rail land.

Project works map 200608
Quay Park

The rail layout will be changed to provide separate rail access to the Ports of Auckland freight yard. This will enable more operational flexibility and to allow for the separation of freight and passenger trains.

Small W2POA map 200608