The Third Main line
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
Our project team are on track for the Third Main to be open following the 2025 Easter Rail Closure. Following this, we will be running test trains along this line.
Stay safe, stay away
There are many benefits to electrification of the track, but overhead electric lines carry 25,000 volts of electricity - this is 100 times more powerful than the electricity in your home.
Electricity can arc (jump) across gaps or pass through objects and water. If you come too close, or touch these lines, it will cause serious injury or death.
Never try to touch the lines, throw anything at them or dangle items from bridges above them.
If you have children, make them aware of the dangers. Never play with kites, balloons or other high reaching items near overhead lines.
If you live next to the rail tracks:
- Be aware of your distance from the lines if you are working at your property boundary. Always keep at least a 4 metre distance.
- Be careful when water blasting at your boundary – direct the water down.
You may require a KiwiRail permit if:
- You want to trim a tree on your property and are concerned it may come into contact with the lines or infrastructure.
- You want to construct scaffold within 8 metres of the lines.
- If you plan to use machinery with moving parts and might encroach on the minimum 4 metre distance.
For more information about permits please visit our Permit to Enter page
The project in detail
Middlemore Station Upgrade
Middlemore Station is being upgraded as part of the Wiri to Quay Park Third Main Line project, which is funded by the government’s New Zealand Upgrade Programme (NZUP).
The station upgrade will be delivered in stages to minimise disruption and allow it to remain in use.
The changes will improve accessibility around the station for everyone, including public transport users, Hospital staff and visitors, and local school students.
For more information, visit : Middlemore
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 started in late 2021 and are largely complete.
Quay Park
The rail layout is being changed to provide separate rail access to the Ports of Auckland freight yard. This will allow for more operational flexibility and for the separation of freight and passenger trains.
To create space for the new track layout at the approach to Quay Park, a small number of trees alongside Tamaki Drive, including Pōhutakawa, need to be trimmed or removed. KiwiRail has worked hard to limit the number of trees affected and will plant about 35 new trees at an alternative safe site.
