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Project delivery & construction

Construction of the early works package on Albert Street and at Britomart started in December 2015 and June 2016 respectively. The main works are expected to start in 2017/18, with completion in 2023/24.


Project phases


CRL project phases


Albert Street from Customs Street to Wyndham Street construction timeline

December 2015 - April 2017 (estimated)

New stormwater pipe in Albert Street
  • Pedestrian access maintained. Impacts traffic lanes at the junctions of Albert and Victoria Streets, and later at the junctions of Albert and Wellesley Streets. Swanson Street from junction with Albert Street to Mills Lane closed to traffic.

June 2016 - January 2019 (estimated)

Britomart to Downtown Shopping Centre (DSC)
  • Closing Lower Queen Street completely to vehicle traffic before constructing tunnels under Lower Queen Street.
  • Construct temporary facilities at rear of Britomart Station before closing Britomart front entry.
  • Underground walkway removed between Britomart and DSC.
  • Pedestrian and cyclist access always maintained.
  • Buses moved from Tyler, Galway and Lower Queen Streets to new locations.
  • No left turn for general traffic from Quay Street into Albert Street.
Downtown Shopping Centre (DSC)
  • Precinct Properties develop their site constructing retail centre, commercial tower and the CRL tunnels below.
Albert Street from Custom Street to Wyndham Street
  • Construct tunnels with cut and cover trenching across Custom Street and up Albert Street to the south side of Wyndham Street.
  • Pedestrian and cyclist access always maintained.
  • Essential traffic access maintained.
  • All bus routes moved from this construction area to new locations.
  • Reinstate Albert Street as a boulevard with bus priority lanes and wider footpaths.

Tunnels

Crl Vertical Alignment Diagram

  • The alignment of the tunnels generally follows the roads to minimise the amount of private property affected by the project.
  • Due to the gradient of the landscape between Britomart and the western line at Mt Eden and the limiting climbing capacity of the electric trains, the twin tunnels will vary in depth. 
  • At each end of the tunnels (Albert Street and Mt Eden) it will be shallow enough to construct the tunnels using the ‘cut and cover’ method (building from the surface).
  • Cut and cover tunnels will be built by installing retaining walls to retain the soil and stop water from entering the site. Tunnels will be constructed, then the concrete floor, walls and roof will be cast and the completed structures backfilled.  When the tunnels reach Mt Eden, they will appear at the surface as ‘dive’ structures (like New Lynn Station).
  • Where the tunnels are deeper, it is likely that they will be constructed using a 7m diameter tunnel boring machine (TBM).
  • TBM projects require large backup areas to get the excavated material out of the tunnel and the supplies in, including precast lining sections. The backup area will be located at the Mt Eden end rather than Albert Street.  For that reason, both tunnels will likely be excavated from the southern to the northern end.
  • Road header machines will be used when the tunnels reach the station box or when the tunnels diverge.

Connection with the Western line around Mt Eden

The Mt Eden Station will be closed and completely rebuilt to allow the CRL to connect in both westerly, towards Swanson and easterly, towards Newmarket. To accommodate the CRL connections, the Western line will be rebuilt between Dominion Road and Mt Eden prison. This will be a lengthy and complex process involving multiple realignments of the track, overhead line and signalling systems.


Construction methods

There are two main construction methods proposed for the City Rail Link:

  1. Cut and cover where the tunnels are dug from the surface.
  2. Tunnelling using a TBM, which travels at some depth below the ground and significantly reduces impacts.

Tunnel Boring Machine 500

These will be used in different areas:

  • Cut and cover near Mt Eden station where the underground tunnels need to rise to the surface to meet the existing Western line.
  • Cut and cover along Albert Street where it is likely to be too shallow for a TBM and there are utilities running down its length.
  • Tunnelling by TBM from Mayoral Drive to an area beyond Symonds Street between New North and Mount Eden Roads.

The main construction area will be at the southern end of the project adjacent to New North Road. The tunnel will be bored from this end to Mayoral Drive, the equipment dismantled and returned to the start for the second tunnel bore. Spoil from the tunnels will be removed from the Eden Terrace end.

There will be smaller localised construction yard areas at Downtown and near the three stations.

Watch a visualisation of the cut and cover construction process in Lower Albert Street


Pipe jacking

Pipe jacking new stormwater main on Albert Street

A major stormwater diversion is needed before the CRL’s cut and cover tunnels along Albert Street can be constructed.

A new stormwater main will be constructed along the eastern side of Albert Street, between Swanson and Wellesley Streets. It will be constructed by pipe jacking (microtunelling), replacing the existing line which currently runs under Albert Street. The pipe jack work is planned for December 2015 to February 2017.

How pipe jacking works

Pipe jacking is a trenchless construction method used to install pipelines beneath highways, railroads, runways, harbours, rivers, and environmentally sensitive areas. 

A micro-tunnel boring machine (MTBM) will drill a small tunnel under Albert Street installing the pipe as it goes.

Micro-tunnelling requires a launch and reception shaft. The launch shaft will be located on the corner of Albert and Victoria Streets. There will be reception shafts at Swanson and Wellesley Streets, each section will take approximately six months to complete. Powerful hydraulic jacks push specially designed pipes through the ground behind a cutting head that excavates the ground at the same time. 

Benefits of pipe jacking

The micro-tunnelling and pipe jacking techniques provide a robust, finished, reinforced concrete pipeline as the tunnel is excavated whilst providing continuous ground support and minimising potential ground movement.

Safety is a prime advantage, especially in urban settings. Using an MTBM to excavate the ground, keeps workers out of the tunnel, providing a far greater level of control over the rate of excavation and the management of different ground conditions.

City Rail Link pipe jacking illustration


Construction impacts

Construction will be typical of large infrastructure projects:

  • Potential adverse effects during construction will be significant but temporary and localised.
  • Construction period is likely to be five to six years and may take place at a number of locations simultaneously but not at all sites for the entire period.
  • Longer term effects will be, in general, significantly positive.

Adverse effects during construction, which can be managed, include:

  • Changes to vehicle, pedestrian and cyclist movement and access.
  • Disturbance from noise and vibration.
  • Human health from removal of any contaminated soil.
  • Social effects.

Get details of the changes to transport as the project rolls out.


Safety assurance on the CRL project

Systematic approaches to managing safety assurance are well established on overseas railway systems, with the European Standard EN50126 commonly used as a framework for managing safety throughout the project asset lifecycle.

This approach is being used for the City Rail Link project and is intended to not only assure a high standard of safety in design but also anticipates the requirements of forthcoming changes to NZ health and safety legislation.

The New Zealand Transport Agency (NZTA), in their role as the NZ Rail Safety Regulator, has mandated Independent Safety Assessment for the CRL project. The Independent Safety Assessor’s role is to verify that the required level of safety and quality is achieved by all parties concerned to ensure the project is implemented to the required safety standards. These standards include, but are not limited to:

  • EN50126 - Railway Applications the Specification of Reliability, Availability, Maintainability and Safety.
  • EN50128 - Railway Applications Safety Software for Railway Systems.
  • EN50129 - Railway Applications Safety for Signalling and Communication Systems
  • IS0 31000 - Risk Management.
  • ISO 9001 - Methods of Quality Management.
  • ISO15288 - Systems & Software Engineering.

The supplier(s) will carry the overall responsibility for the detailed verification and validation (V&V) activities and the evidence of safety within its contractual scope, whereas the Independent Safety Assessment will focus on the judgement of whether the supplier(s) V&V and Safety Management Organisation has applied the appropriate processes and techniques in line with the requirements of the standards.

It is the goal of the Independent Safety Assessment to put the Safety Authority (NZTA) into a position to grant the allowance for operations (licensing) after the finalisation of all necessary evaluations, examinations, analyses, inspections, and tests.


For more information

Contact Auckland Transport