Rail Network Rebuild

KiwiRail is undertaking a major upgrade of the Auckland rail network over the next few years, in preparation for the opening of the City Rail Link.

The City Rail Link (CRL), which is expected to be completed by the end of 2025, will allow even more frequent and convenient Auckland Transport electric commuter trains across the city.

However, to deliver these benefits work needs to be done to remove temporary speed restrictions and raise the existing network up to a modern metro standard.

With funding from Waka Kotahi, KiwiRail has developed a programme of work – the Rail Network Rebuild - which is focussed on replacing the foundations under the tracks. We are also improving drainage in the rail corridor, to limit disruption from weather events.

This work will result in more reliable and smoother train rides across the city and is crucial to allow more frequent trains, to come with CRL.

Carrying out significant work like this on a live network that operates 24/7 is extremely difficult. For example, if we were to do this work in our current evening and weekend maintenance windows, it would take almost two decades to complete.

To get the majority of the work done before CRL opens, KiwiRail and Auckland Transport have made the difficult decision to close some rail lines, or sections of line, to electric commuter trains while this work is undertaken.

RNR Stage 1 excavating existing formation near Penrose Station
Stage 3 complete

Stage 3

Stage 3 will involve work on the Western Line and the Southern Line.

Instead of closing sections of rail line for long periods of time, we are able to work in evenings, on some weekends, and over Labour Weekend and the quiet Christmas period. After these initial works teams move to the Southern Line. We return to complete Western Line work in March. We will work during weekdays on the Western Line for about nine weeks – but we can do this while keeping one track open so that some trains can keep running.

Stage 3 is complicated and there will be some disruption as we undertake this crucial work - however it will be much less than that experienced by Auckland commuters in previous stages.

RNR Stage 3 will start on Labour Weekend and is expected to continue into June 2024. Work will be done on different parts of the Western and Southern lines at different times. Alternative transport options will be provided as required; details will be provided to customers ahead of work beginning.

  •  Stage 3a: Major upgrades to the Western Line between New Lynn and Newmarket, including replacing aging formation.
  •  Stage 3b: More minor track drainage-focused work on the Southern Line between Pukekohe and Puhinui, to improve resilience and the performance of the rail foundations in this low-lying part of the network.

Stage 3 work timing
• Labour Weekend into December 2023 – Stage 3a starts. Working mainly at nights. On some nights commuter services will stop running earlier than usual. There is a full network-wide closure over Labour Weekend and one additional weekend closure on the Western Line
• Full Network Christmas Closure: 26 December 2023 – 14 January 2024 – Stage 3a continues• 15 – 19 January 2024 – Stage 3a continues. The Western Line will remain closed for an additional week for RNR work.
• Late January – March 2024 – Stage 3b starts. Working between Papakura and Puhinui, mainly at nights, where commuter services will stop running earlier than usual. There will also likely be a number of weekend line closures.
• Early March – May 2024 – Stage 3a completion. Working between Avondale and Morningside. Metro trains will be able to run on one (of the two) Western Line tracks, though they will be less frequent than usual.
• Late May – late June 2024 – Stage 3b completion. Working between Pukekohe and Papakura. Commuter services are not affected as this section of line is already closed for work extending overhead electrification.

Frequently Asked Questions for Stage 3 can be found here.

Stage 2 completed

Work for Stage 2 on the Eastern Line has included:

  • 6,932 metres of formation (the rock foundation below the track) has been excavated and replaced.
  • 19,110 metres of ballast (the larger rocks the tracks sit on) has been replaced.
  • 24,678 metres of drainage has been improved.
  • 1,383 metres of rail and sleepers has been replaced.
  • Around 130 KiwiRail staff and contractors are working on RNR Stage 2

Find out where our teams are working and what we are doing here.

What we are doing

Rail Network Rebuild cross section graphic

The Rail Network Rebuild is challenging:

  • Rail lines, sleepers and turnouts (which allow trains to switch between tracks) lifted away;
  • Existing formation (compacted gravel that forms the base of the rail line) and ballast (the rocks the tracks sit on) dug out;
  • New formation brought in and compacted to form a firm and resilient base;
  • New ballast brought in and compacted
  • New drainage to prevent future deterioration of the formation;
  • The rails, sleepers and turnouts put back, aligned for safe and smooth train running.
This video shows how we replace the foundations under rail tracks.

Wherever possible we’ll also do proactive maintenance – such as replacing sleepers and trimming vegetation that would otherwise need to be dealt with in the coming years – and using the line closures to complete other rail related projects.

All railways require ongoing maintenance but we are thinking ahead and trying to avoid the need to come back and cause further disruption in the years ahead.


These photos illustrate some of the different types of work that go into the Rail Network Rebuild (RNR) .

Rail Network Rebuild work involves removing track and digging out the original formation (foundation), adding stabilizing mesh, putting in and compacting new formation, then replacing the rails and sleepers and then re-ballasting. This example at Sylvia Park includes adding a new crossover, which will improve flexibility on the network.


Using technology to get the job done quickly

To renew formation quickly, KiwiRail is using a range of specialist machines and technology. These include:

Panel lifter

The panel lifter can pick up and put down up to 75 metres of straight sections of track and sleepers at a time.

Panel Lifter

Stabilisers shake and consolidate the track formation, to ensure new formation is stable.


Tamper machines measure the track placement, lift it, and pack the ballast underneath to hold it in place. It helps create a smoother ride for passengers and freight.

Rail grinder

Rail grinders smooth irregularities in the tracks and restore their profile, so they last longer. It also helps to improve the ride for passenger and freight services.

Rail grinder

Without suspending frequent commuter services, it would be impossible to safely use much of this time-saving technology.  

Frequently Asked Questions.