The City Rail Link is currently under construction with completion targeted for around 2022.


The effects of CRL construction are now very evident, with Albert Street and Downtown major construction zones. For the interested observer, most of that construction work is going on behind large hoardings so much of what you will see as you commute through the city, will be safety barriers, acoustic shields and traffic cones.


Like us, many of you will be very interested to follow construction and gain a better insight into what is happening. It is difficult to miss the heavy civil construction machinery moving about the city centre as the CRL, together with many other private developments develop.


The CRL is an exciting transformational project, in addition to keeping our CRL photo galleries updated and relevant, Emerging Auckland has compiled a simple A - Z of everything to do with 'City Rail Link'.  Hopefully you will find our brief explanation of the construction processes that will deliver the project interesting.


We will include useful engineering terms and give you a general overview of the wider project, and update the index as the project advances.




Accessibility within the context of CRL refers to city centre accessibility, the ease of commuting to and from the city centre.  The CRL will improve city centre access.


To be able to construct the CRL, land from about 200 below ground (sub strata) and 88 surface properties were identified as required when the route was determined. Fortunately, much of the land required to build and operate the CRL is located below roads or on property already owned by Auckland Transport or Auckland Council.


In New Zealand as a land owner you own that land right through to the centre of the earth. To construct tunnels for CRL below ground land is required to be purchased requiring a process of negotiation between AT and affected landowners.


In New Zealand ‘The Public Works Act’ sets out the process for negotiation to acquire land, endeavouring to provide a fair and equitable outcome for property owners.


The acquisition process takes place after all required consents for the use of the land have been granted, or a designation has been provided for by the territorial authority.


‘Agglomeration’ in simple terms refers to the formation of a large group (i.e. a City), or a collection (of people). In the context of Urban economics, agglomeration is about creating effective density within a certain area and suggests greater benefits for business is achieved through locating within closer proximity ('agglomerating') to achieve certain economic concessions. Agglomeration economics is central to the explanation of how cities increase in size and population.


The CRL will provide greater, more reliable city centre access and enabling more opportunities for businesses to co-locate within closer proximity and benefit from agglomeration.


In railway terms, ‘alignment’ refers to ‘track geometry’ or railway track layouts and the process of design, construction and planning for ongoing maintenance of rail tracks.

Aotea Station

Aotea Station is a proposed two level underground station running parallel to and under Albert Street between Victoria and Wellesley Streets with entrances East and West of Victoria Street at the Albert Street intersection, with a Southern entrance on the Corner of Wellesley Street at the location of the former Griffiths Building.


Key features include a 150-metre platform directly under Albert Street between Wellesley and Victoria Streets, underground levels (mezzanine concourse and platform) will connect via lifts and escalators with entrances from street level at both ends. Possible future connections from concourse level to Sky City and the future NDG building on the south-east corner of Albert and Victoria Streets. Provision for future property development (circa 17-storey building) above the southern entrance on the south-east corner of Wellesley and Albert Streets.

Interior view - proposed Aotea Station

APB&B Report

At the request of the then Auckland Regional Transport Authority (ARTA) and KiwiRail, AECOM, Parsons Brinckerhoff, Beca and Hassell (APB&B) were commissioned to prepare a business case investigating the economic viability of using a tunnel to improve rail linkages into the Auckland CBD. The business case proposed a tunnel through the CBD with three new railway stations at key locations configured to provide maximum rail coverage ensuring most CBD areas being accessible to stations within a 500 metre walk.


The final business case strongly supported a ‘rail link’ and the APB&B Report is now a founding document for the CRL. Read the APB&B report

Auckland City Centre Master Plan

In 2012 Auckland Council adopted The Auckland City Centre Masterplan (the Plan).  The Plan was drafted around a series of assumptions on the future development of Auckland City including estimated population growth and housing, transport and civic infrastructure requirements and sets out the vision for Auckland over the next 20-year period to around 2030.  The plan defines a clear pathway towards taking the Auckland City Centre forward as the cultural, civic, retail and economic heart of Auckland.


The plan looks at the opportunities and challenges inner Auckland faces and puts into place a plan of action centered around eight strategic moves required to transform the Auckland City Centre and fringes. The Plan ultimately seeks to develop a competitive city within a world class urban environment. The Plan sets out the way forward to deliver the ‘vision’ and transform Auckland into a world class metropolitan city.

Auckland Council

Auckland Council is the Local Authority for Auckland and the CRL is an Auckland Council Project to be delivered by Auckland Transport as the ‘transport arm’ Council Controlled Organisation.

Auckland Plan

The Auckland Plan was drafted and adopted by the Auckland Council in March 2012 as a foundation guide for Auckland’s future over the next 30 years. The Plan sets out ways to manage city issues such as transport, deal with housing shortages, creating opportunities for children and young people, creating more jobs and protecting the environment

Auckland Transport

Auckland Transport is the ‘transport arm’ Council Controlled Organisation responsible for the delivery of the CRL.



Britomart Temporary Station Entrance

Construction of a temporary station entrance and concourse to the east of the ‘glass box’ behind the Britomart Transport Centre (BTC) commenced in May 2016 and was opened on 9 January 2017 with the main former Central Post Office entrance closing on 16 January 2017 until 2019 to allow for significant works to underpin the building and construct the CRL tunnels.  On completion this temporary facility will serve as the main station entrance and customer service centre during the Contract 1 Enabling Works programme.



















Sodium Bentonite is an absorbent clay that grows and expands when wet.  In civil engineering applications bentonite is used as a mineral hydraulic barrier in diaphragm walls, foundations, tunneling, horizontal directional drilling and pipe jacking.


Bentonite slurry walls (also known as diaphragm walls) are used in construction, where the slurry wall is a trench filled with a thick mixture of bentonite and water.  A trench that would otherwise collapse due to the hydraulic pressure in the surrounding soil is prevented from collapsing as the bentonite slurry balances the hydraulic pressure. Forms for concrete, and rebar, can be assembled in a slurry-filled trench, and then have concrete poured into the form. The dense liquid concrete displaces the less-dense bentonite slurry and causes the latter to overflow from the trench. The displaced bentonite slurry is then channeled to a recycling unit from which it can subsequently be reused in a new trench elsewhere on the construction site.


Two bentonite recycling units will be established within the Lower Queen Street area to aid with construction of diaphragm walls.

Bentonite recycling tanks within Lower Queen Street

Britomart Transport Centre

Britomart Transport Centre (BTC) is Auckland's major transportation hub. Situated at 8-10 Queen Street, within the ‘Britomart precinct’, it is used for both bus and train travel.


The BTC was designed by California architect Mario Madayag in collaboration with local Auckland architects Jasmax and constructed within the former Auckland Chief Post Office (CPO).


Construction of Britomart commenced in October 2001, involving 14 km of piling, some being 40 m long and driven 16 m into the underlying bedrock, mainly to provide good earthquake protection, and to future proof the area for potential later construction of buildings on top of the station. 200,000 cubic metres were excavated for the station, and 40,000 cubic metres of concrete poured. The station has a site area of 5.2 ha.


Mid- 2016, construction of a temporary station concourse commenced, which was completed and opened on 9 January 2017.  The temporary building will serve as the main station entrance and customer service centre while construction of the CRL tunnel portals takes place under the historic CPO Building. The CPO building will be fully reinstated.

Former Central Post Office - Sir George Grey Special Collections, Auckland Libraries, 1-W1755

Business Case

A business case sets out the reason for initiating (in the case of the CRL) a project. A business case is a structured written, well articulated document which clearly defines the logic or reasoning to progress a particular project or business. A business case can be produced in summary, short or full versions depending on the degree of detail required by a particular audience. Generally, whenever resources or money are required, particularly public money, to support a specific project or business need, a sound business case, or documented argument, is required to convince the relevant decision maker(s) to support and approve action.


As the CRL will be funded jointly between Local and Central Governments AT is negotiating a joint business case with Government.


AT’s internal summary business case to facilitate the Gateway Review process prior to letting construction contracts has been released.  Read the CRL Business Case Summary here.

Timelapse of constructing the temporary Britomart Transport Centre station entrance - December 2016

Bentonite recycling tanks at the Commercial Bay development site in Lower Queen Street

Interior view -Britomart Transport Centre station entrance - January 2017




A caisson is a watertight retaining structure used, for example, the purpose of gaining access to the bed of a stream, or in the case of the CRL, forming reception shafts for the pipe jack works along Albert Street. Segmented caissons will be formed to create permanent portal entries to enable the MTBM to bore the new stormwater pipes and on for permanent access for maintenance and safety purposes. Two caisson shafts will be created, one at Wellesley Street and a second shaft at Swanson Street.


Segmented caisson similar to the Wellesley and Swanson Street pipejack shafts

Video showing construction methods for segmental caisson shafts

City Centre Future Access Study (CCFAS)

The City Centre Future Access Study (CCFAS or Study) refers to a study undertaken during 2012 by Sinclair Knight Merz (SKM), commissioned by Auckland Transport to develop a robust and achievable multimodal programme for transport into the Auckland City Centre.  The report produced thorough analysis of transport alternatives and identifies the optimal mix of modes to meet future demand. This included consideration of the prioritisation and sequencing of projects around public transport modes. In particular, these were, underground rail infrastructure, surface bus infrastructure and underground bus infrastructure.


The CCFAS strongly supported the case for the CRL and is a founding document.

Civil Engineering

Civil engineering deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings.

Commercial Bay Development

Commercial Bay is a development by Precinct Properties Limited to be constructed on the site of the ‘Downtown Shopping Centre’ (DSC). Construction commenced in June 2016, beginning with demolition of the former Downtown Shopping Centre.


Commercial Bay is being constructed by Fletcher Construction who will also construct a portion of CRL tunnels through the Commercial Bay site to Auckland Transports design and specification.


Commercial Bay is due to open in late 2018 and includes a 39 level, 39,000sqm landmark office tower and 18,000sqm of retail.

Precinct Properties Limited - Commercial Bay Development

Commercial Bay Development - Lower Albert & Quay Street intersection


A consortium is a short-term arrangement between several companies from the same or different industry sectors who pool their human resources, skills and knowledge to undertake a large project that benefits all members of the group. A consortium lasts an agreed period to complete a project or contractual obligation.

Construction Contract 1

Construction Contract 1 involves decommissioning and later restoring the former Central Post Office station building, constructing a ‘temporary station entrance’ to the rear of the CPO, constructing two rail tunnels under the CPO and through Lower Queen Street to the eastern ‘stub’ of the Commercial Bay site and from the western ‘stub’ of the Commercial Bay site to Customs Street.  Construction Contract 1 commenced in July 2016 with construction of the temporary station concourse and accommodation facility. That programme was completed on 9 January 2017, with a changeover of operations from the CPO to the new temporary on 16 January 2017.

Construction Contract 2

Construct Contract 2 involves construction of CRL tunnels by cut and cover trenching across Custom Street and up Albert Street to the south side of Wyndham Street and a ‘pipe jack’ programme along Albert Street from Wellesley to Swanson Street. Utility diversions to enable the pipe jack programme commenced in December 2015 with the pipe jack and cut and cover trenching works being undertaken through 2016.

Cut and Cover tunnelling

Cut-and-cover is a method of civil engineered construction for shallow tunnels where a trench is excavated and roofed over with an overhead support system strong enough to carry the load of what is to be built above the tunnel. There are two basic forms of cut-and-cover tunneling, the ‘Top-down’ or ‘Bottom-up’ method.  The CRL tunnels will be constructed using the bottom-up method where a trench is excavated and the tunnel is constructed through it, then carefully back-filled and the surface reinstated.  CRL tunnels will be approximately 8m below the road surface.

Albert Street cut and cover tunnel

Video showing Albert Street cut and cover tunnelling construction sequencing

Segmented caisson shaft at Swanson Street

Caisson shaft

Construction Contract 1 -  temporary Britomart Station entrance

Britomart Transport Centre - temporary Commerce Street station entrance

Acoustic shed & gantry crane structure - Corner Victoria & Albert Streets

Inside the acoustic shed

OMS Shaft  (18m deep at completion) - Corner Victoria & Albert Streets

OMS Shaft - soldier piles and timber lagging




A designation is a planning technique used by Ministers of the Crown, local authorities and network utility operators approved as requiring authorities under s167 of the Resource Management Act (RMA).  Only requiring authorities can seek designations for land.


Designations enabled central and local government to get planning authorisation for public works and protected land for future public works.


The CRL designation runs from Britomart, to Albert, Vincent and Pitt Streets, then crosses beneath Karangahape Road and the Central Motorway Junction to Symonds Street joining the western line at Eden Terrace.

The City Rail Link designation from Britomart to Eden Terrace (Mt Eden)

Diaphragm Wall

A diaphragm wall (or D-Wall) is a continuous wall constructed in the ground and typically to form an underground barrier or structure. Diaphragm walls are constructed through a narrow trench, excavated in ground and supported by an engineered fluid (typically a sodium bentonite mud) which is later replaced by a permanent material (concrete). A diaphragm wall would typically be constructed as a ‘perimeter’ to prevent water ingress, for example.


Diaphragm walls will be created under Lower Queen Street from the CPO Building to enable CRL tunnels to be formed.

Constructing a diaphragm wall with steel reinforced cage - Commercial Bay

Diaphragm walls in cut and cover tunnel construction



Early Contractor Involvement

In April 2015 Auckland Transport award two Joint Venture Design and Construction contracts to provide early input into the CRL design for two ‘early works’ or ‘enabling works’ packages to be undertaken in the Downtown area. Downer NZ and Soletanche Bachy JV and Connectus (McConnell Dowell and Hawkins JV). Following design input a two negotiated contracts will be awarded to construct the City Rail Link from Britomart to Wyndham Street.

ECI – Contractor 1

Downer NZ and Soletanche Bachy JV were chosen to progress the CRL work through and under Britomart Station and Queen Street to the Downtown Shopping Centre site.  Construction commenced in July 2016.


Contract 1 includes establishing temporary accommodation for Britomart Station’s ticketing and customer service operations, the underpinning of the historic former Chief Post Office building, to allow the construction of the rail tunnels beneath and reinstating Britomart Station and upgrading urban space and surrounding roads.

ECI – Contractor 2

Connectus (McConnell Dowell and Hawkins JV) will construct the cut and cover tunnels under and along Albert St from Customs Street to Wyndham Street. Contract 2 commenced in December 2015 with a ‘pipe jack’ component relocating a major storm water line in Albert Street between Swanson and Wellesley Streets and strengthening a bridging a section of the Orakei Sewer Main at the intersection of Victoria Street and Albert Street.



Fletcher Construction Limited

The construction contractors contracted to construct the Commercial Bay Development on the former Downtown Shopping Centre site for Precinct Properties Limited. Commercial Bay is bounded by Customs Street West, Lower Albert Street, Lower Queen Street and Quay Street.



Gateway Review Process

A Gateway review is an assurance process for significant projects where major investment is made. A Gateway Review is a confidential ‘review’ undertaken by experienced 'peers' to provide a fresh perspective of the project. The Gateway Review provides checks and balances at strategic points (gateways) throughout a project’s life-cycle, measuring progress and the likelihood of successful delivery of intended outcomes. The review assesses the robustness of the project and, if necessary, contributes to improve its ultimate performance.


As part of the review the project's significant stakeholders are interviewed and project documents examined. A Gateway Review is not an official audit but a detailed technical progress review.



Integrated Transport Programme (ITP)

Auckland's Integrated Transport Programme sets out the 30-year investment programme to meet the transport priorities of the Auckland Plan, from 2012 - 2041.


The CRL is key to delivery of the ITP. Read the 2012 - 2041 ITP here




Karangahape Station

A deep (circa 30-metre) station situated along Mercury Lane on the site of the current Green Party Headquarters.




Long Term Plan (LTP)

The Auckland Council Long-term Plan 2015-2025, is the 10-year budget for Auckland, outlining investment in Auckland city over the next decade. The CRL is key to delivery of the LTP. Read the Long Term Plan here

Lower Queen Street

Lower Queen Street is the portion of Queen Street immediately adjacent to the former Central Post Office building and Britomart Transport Centre.


Lower Queen Street was completely closed to to vehicle traffic on April 2016.  The area immediately adjacent to the BTC is being used as a public activation space prior to the construction of CRL tunnels and will be reinstated as a permanent public square at the conclusion of CRL works.

Lower Albert Street

Lower Albert Street is the portion of Albert Street parallel to the Commercial Bay Development and within the CRL footprint. A portion of CRL tunnels will be constructed in Lower Albert Street.


Lower Albert Street will be reinstated as a bus interchange accessed by 24/7 unpaid pedestrian link from Britomart, through the Commercial Bay site.



Mana whenua

A partnership with eight local iwi groups was established in 2012. The CRL project team hold monthly design meetings with local iwi who self-identified their interest in the project. Te Ākitai, Te Kawerau a Maki, Ngāti Maru, Ngāti Paoa, Ngati Te Ata, Ngai Tai ki Tāmaki, Ngāti Tamaoho and Ngāti Whātua o Orakei are all represented through a mana whenua forum and are actively participating in designing CRL infrastructure.

Market Sounding (CRL Main Works Procurement)

Late 2015 Auckland Transport invited established companies active in the rail sector to register their interest to provide input into the proposed procurement approach for CRL main works. Input from the industry was sough around the project packaging, contract and delivery models, and the construction programme. Read the CRL Market Sounding Notice here


Following selection, during January and February 2016 Auckland Transport engaged with construction-consulting industries, through a series of market sounding workshops.


The primary objectives of ‘market sounding’ was to obtain early feedback on potential procurement considerations, discuss options, gather information to refine the procurement strategy and test the anticipated programme and process.


This industry-facing approach is in line with international rail industry practice and will help ensure a robust outcome for the project's delivery.

Mechanical & Electrical Engineering

Mechanical engineering deals with the design, analysis, manufacturing, and maintenance of mechanical systems. It primarily involves the design, production, and operation of machinery. Electrical engineering generally deals with the study and application of electricity, electronics.

Micro tunneling

Microtunnelling is a method of digging to construct small diameter utility or services tunnels using microtunnel boring machine (MTBM), operated remotely.

Microtunnel Boring Machine (MTBM)

Microtunnel boring machines (MTBM) are very similar to tunnel boring machines but on a smaller scale. The microtunneling machine is driven and monitored remotely from the surface.  The CRL MTBM 'Valerie' is an Akkerman Open Face 720B with a cutting diameter of 2200mm and weight of 13tonne.

Mt Eden Station

The CRL will redevelop the existing Mt Eden railway station at Eden Terrace, adding a new platform and two level station building. The new station will connect passengers at Mt Eden Station to the CRL which previously bypassed them. This will enable improved reliability with the provision of a separated east-west junction so train lines won’t need to cross over each.


The new station will be developed around a trench similar to New Lynn and see the creation of a new road.


Design change during 2014 favoured a redeveloped Mt Eden Station replacing the earlier proposed underground Newton Station, reducing construction disruption in Upper Symonds Street by up to 18 months. Much of the area surrounding Mt Eden Station will be acquired, with buildings removed to enable construction of the CRL tunnel portals and connection to existing North Auckland Line.


"The improved design will connect passengers at Mt Eden Station to the CRL which previously bypassed them and improve operation reliability through the provision of a separated east-west junction so train lines won’t need to cross over each other.

Valerie MTBM

'Valerie' MTBM - being lowered into the Vic 1 shaft ready for commissioning - December 2016



North Auckland Line (NAL)

The 'North Auckland Line' (NAL) is a major section of New Zealand's national rail network. The three local lines on the NAL are the Onehunga Branch line which connects with the North Auckland Line at Penrose and forms part of the route of Onehunga Line suburban passenger train services operating between Britomart and Onehunga via Newmarket.


The Newmarket Line meets the North Auckland Line in Newmarket and provides a connection with Britomart; and the portion of Auckland's Western Line that runs from Newmarket westward to Waitakere.


The first section was opened in 1868 and the line was completed in 1925.

Notice of Requirement

A notice of requirement (NoR) is a proposal for a designation (route). A NoR has an interim effect, in that it protects the land for the designated purpose until the designation is confirmed and included in an operative district plan (s178).


AT gave notice on 23 August 2013 to Auckland Council of its requirement to designate land in the Auckland District Plan (Operative Auckland City Central Area Section and Operative Auckland City Isthmus Section) for the construction, operation and maintenance of the City Rail Link (CRL or the Project). A total of six NoRs were publically notified on 25 January 2013 and submissions closed on 19th March 2013.


On 5 March 2014 Auckland Transport welcomed a unanimous recommendation by independent planning commissioners that the land required to build, operate and maintain the City Rail Link be set aside for the project, subject to conditions that address issues raised by submitters.


On 10 November 2015, following six appeals heard in the Environment Court, the CRL designation was confirmed. Detailed information relating to the CRL NoR is available here

NZ Transport Agency (NZTA)

The NZ Transport Agency (NZTA) is a Crown entity governed by a statutory board. The purpose of the NZTA is to deliver transport solutions for New Zealand on behalf of the government.

NZ Rail Safety Regulator

NZTA are the Rail Safety Regulator for New Zealand with responsibility for ensuring safety on New Zealand's rail networks including licensing all organisations that operate on and/or provide access to rail networks. Every organisation whose railway has one rail, or a set of rails with a gauge of 550 millimetres or greater between them, must hold a rail licence



Orakei Main Sewer

The Orakei Main Sewer (OMS) was originally constructed in 1910, and runs from Avondale, via Herne Bay and onwards to Hobson Bay, a total of over 8 km. The OMS varies in size from 525mm circular to 2.4m x 1.5m egg shape.


Part of CRL works will include strengthening and bridging a section of the OMS at Victoria Street West, to be undertaken as part of the Construction Contract 2 pipe jack programme.

Sir George Grey Special Collections, Auckland Libraries, AWNS-19100804-16-4

The original Orakei Sewer Main running along the foreshore at Orakei, 1910




Patronage within the context of CRL refers to the number of fare paying passengers using the Auckland Metro Railway.


During the past decade, rail patronage has increased from 2.2 million trips a year to 15,887,665 passenger boardings in the 12-month period to March 2016. Patronage during March 2016 was 1,638,658, an increase of 73,866 boardings or +4.7% on March 2015.


Patronage for rail services is increasing at a rapid rate but further growth of the rail system, including increases to train frequency, will be constrained by the current rail network, particularly due to the ‘dead end’ at Britomart, which limits the entire network’s capacity.


The CRL will join up the rail network, allowing trains to run both ways through Britomart, doubling the number of trains that can run on the network.

If the Britomart dead end wasn’t removed, the Auckland commuter rail network is limited to 15,000 passengers an hour. By removing the dead end the CRL will allow 30,000 people an hour during peak commuting. By comparison, a single motorway lane can carry only 2,400 people an hour.

Pile driver

A pile driver is a mechanical device used to drive piles into the ground (soil) to provide foundation support for buildings or other structures. Pile driving rigs are usually composed of a tall framework in which either a weight is raised and dropped on a pile head or in which a steam hammer drives the pile.

Piling at the Albert & Customs Street intersection

Driving H piles at Vic 2, corner Albert & Victoria Streets

Pipe jacking

Pipe jacking is a trenchless construction method used to install pipelines beneath highways, railroads, harbours, rivers, and environmentally sensitive areas. Generally, pipe jacking involves a micro tunnel boring machine (MTBM) travelling from a launching shaft to a reception shaft.


CRL uses the pipe jacking method to create a new stormwater main along the eastern side of Albert Street, between Swanson and Wellesley Streets with caisson shafts to be constructed at Wellesley and Swanson Street intersections. Two additional shafts will be constructed in Victoria Street to enable strengthening of the Orakei Sewer Main across Albert Street.


In December 2016, 'Valerie' the CRL MTBM was commissioned at Vic 1 and commenced the first leg of pipe jacking from Victoria Street to Swanson Street.  Stage 1 was completed in January 2017 and Valerie will be transported back to Vic 1 to commence Stage 2 of the pipe jack from Victoria to Wellesley Street.

Pipe jacking under Albert Street

Pipe jacking from Victoria Street to Swanson Street

Precinct Properties Limited

Precinct Properties Limited are developing Commercial Bay on the site of the former ‘Downtown Shopping Centre’ and the largest owners of premium inner-city business space in Auckland and Wellington.


Listed on the New Zealand Stock exchange since 1997, Precinct is an established New Zealand business, with around 7,800 New Zealand shareholders who together own around 75% of the company.

Principal Technical Advisor

In 2014 a consortium of engineers and architects led by Aurecon was awarded the role of Principal Technical Advisor (PTA) and contracted to Auckland Transport to works alongside the CRL project team. The role of the PTA is to deliver reference design for the CRL.


The consortium includes Mott Macdonald, Arup and architects Grimshaw & Jasmax.


The PTA provides a range of design services including civil & structural design for bored & cut and cover tunnels, geotechnical, rail alignment, hydrology, geology, architecture for stations, pedestrian modelling, heritage, acoustics, noise, vibration, electrical & mechanical engineering for ventilation, hydraulics and vertical transport, security and building management, signalling, controls, communications, overhead line equipment, traction power, safety & systems assurance including rail safety & human factors, constructability and risk management, programming, rail operations including operational and maintenance, quality assurance, fire engineering, resource management and environmental planning.


Many of the PTA are specialists within the railway industry seconded in for unique project specific skills.


Procurement is the process around acquiring and delivering goods, services and works. It starts with identifying a need and finishes with either the end of a service contract or the end of the useful life and disposal of an asset. The procurement of large contracts, such as construction contracts a tender process is undertaken to ensure a fair and equitable commercial outcome which is often determined by the market itself.


Jargon Buster - Common procurement words & expressions explained



Queen Elizabeth Square (QEII Square)

Queen Elizabeth Square is a public space bounded by the Downtown Shopping Centre, HSBC and Zurich Buildings and opposite Britomart Transport Centre. QEII Square was underutilised due to the effects of shading and during 2015 sold by Auckland Council to developer Precinct Properties for $27.2 million to enable a section of the Commercial Bay development to be constructed on the site. The sale was subject to an Environment Court Hearing following appeal by interest groups.


Auckland Council are committed to providing an alternate public space.

Queen Elizabeth Square 1989 - Sir George Grey Special Collections, Auckland Libraries, 1021-670

Queen Elizabeth Square 1989 - Sir George Grey Special Collections, Auckland Libraries, 1021-207



Reference Design

Reference design refers to a technical level of design that is intended for others to advance. Reference design for the CRL contains all the essential elements; however, future construction companies, for example may enhance or modify the design to achieve constructibility.


For the CRL, reference design has been undertaken by a Principal Technical Advisor (PTA) consortium led by Aurecon and including Jasmax, Grimshaws, Mott MacDonald, Golders and Arup. The PTA comprises a design team of architects and civil, structural, mechanical and electrical engineers and other specialists bought in for their skills unique to rail projects.

Request for Tender

A request for Tender (RFT) is a formal request or invitation to industry from an agency asking for offers from potential suppliers to supply clearly defined goods or services or works. Often there are highly technical requirements and a prescriptive solution. RFT often follows earlier Requests for Information (RFI) as a market research tool, seeking market information to get an idea of the number and type of suppliers and the range of solutions, technologies and products or services they can provide.


In the context of a large infrastructure project like CRL it is essential to understand the construction industry (market) to determine the market’s appetite for, ability to resource and capability to deliver a project of the scale of CRL.


The City Rail Link will be built in two 3.4km-long, twin tunnels up to 42 metres below the city centre. It will extend the existing rail line underground through Britomart, to Albert, Vincent and Pitt Streets, then cross beneath Karangahape Road and the Central Motorway Junction to Symonds Street before rising to join the western line at Eden Terrace.


As much as possible, the project is below city streets to reduce the effects on property owners and heritage buildings. The new line will provide for two new railway stations ‘Aotea’ and ‘Karangahape’, and a redeveloped Mount Eden Station.



Safety Assurance

Safety assurance is the application of safety engineering standards and practices, enforced to minimise the risks of any operational hazards. The standard for CRL is the European Standard EN50126 which will be used as a framework for managing safety throughout the project asset lifecycle


The New Zealand Transport Agency (NZTA), in their role as the NZ Rail Safety Regulator, has mandated Independent Safety Assessment for the CRL project.

Secant Pile Walls

Secant pile walls are drilled shafts (piles) constructed in such a way that the shafts overlap each other to form a wall, an intersection of one pile with another. Secant piles are used to build cut-off walls for the control of groundwater inflow and to minimise ground movement.


Secant walls are effective as a permanent means of retaining the sides of bulk excavations and will form the retaining structure along Albert Street to enable construction of cut and cover tunnels.

Driving secant piles along Albert Street - cut and cover tunnel construction

Piling along Albert Street - December 2016

Soldier piling

Soldier piling is the method used to construct two deep access shafts at the Victoria and Albert Street intersections to create a cavern to enable the Orakei Main Sewer to be bridged and strengthened.


Soldier piles are constructed of wide flange steel H sections spaced at intervals of 2 to 3m apart, driven in prior to excavation. As excavation proceeds, horizontal timber sheeting (lagging) is inserted behind the H pile flanges.

Wide flange steel H Beams

Soldier piling for the OMS shaft at 'Victoria 2' - Victoria Street

Stormwater Main

A new stormwater main is required along the eastern side of Albert Street, between Swanson and Wellesley Streets and will be constructed as part of the Construction Contract 2. The stormwater main will be constructed by pipe jacking (microtunelling), replacing the existing main which currently runs under Albert Street. The pipe jack programme is planned for


June 2016 to February 2017.

Structural Engineering

Structural engineering is concerned with ensuring that buildings or ‘built structures’ are constructed strong and stable enough to resist all appropriate structural loads (e.g. gravity, wind, snow, rain, seismic (earthquake), earth pressure, temperature, and traffic) in order to prevent or reduce loss of life or injury.


Sustainable construction refers implementing processes which are environmentally responsible, sustainable and resource efficient. Sustainability principles should be implemented through a building's whole-of-life, from design, throughout construction, operation, maintenance, renovation, and eventually demolition.


The CRL is being designed and constructed and will eventually be operated to the highest sustainability standards and aims to set a precedent for infrastructure development in New Zealand.


The CRL has implemented an Infrastructure Sustainability (IS) compliance framework to assist with measuring, evaluating and certifying sustainability across the project's design, construction and operation.


More information on CRL sustainability here




An offer to provide goods or services for a specified price, in response to a request for tender.

Tunnel Boring Machine (TBM)

A tunnel boring machine (TBM) also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. TBMs are able to bore through anything from hard rock to sand. Tunnel diameters can range from a metre (micro-TBMs) to around 19m.

Tunnel Boring Machine (TBM)

Typical bored rail tunnel


Tunnelling by TBM will be required to construct the CRL rail tunnels from Mayoral Drive to an area beyond Symonds Street between New North and Mount Eden Roads.


It is proposed that a 7m diameter TBM will be used to bore from the location of the Mt Eden Station to Mayoral Drive (Aotea), then transported back to that site to bore a second tunnel from the Mt Eden Station to Aotea.


Boring from South to North means that spoil will be conveyed and transported away from the city centre.



Unitary Plan

The Proposed Auckland Unitary Plan (PAUP) replaces the existing Regional Policy Statement and 13 district and regional plans, the Unitary Plan will determine what can be built and where, how to create a higher quality and more compact Auckland, how to provide for rural activities and how to maintain the marine environment.


The PAUP sets out to make Auckland a quality place to live, attractive to people and businesses and a place where environmental and social standards are respected and upheld.


It is also the key tool for implementing the Auckland Plan, the 30-year vision and spatial plan to make Auckland the world’s most liveable city.


Read more about the PAUP here

Utility Diversions

In order to clear the way for CRL construction to commence, the diversion or relocation of many essential utility services is required. This includes stormwater pipes, electricity supply cables, telecommunications cables, gas pipes, sewer pipes and any other service conduit that needs to be safely relocated for the benefit of the service providers and their customers.

Time lapse video of progress with Contract 2 progress on Albert & Victoria Streets

Vic 1 site, corner Albert & Victoria Street



Vertical Alignment

An accentuated view of the CRL route gradient from Britomart through to the Mt Eden Station trench.

Emerging Auckland is a Development Tracker - documenting, tracking  progress and 'showcasing' current and planned private construction and civic infrastructure developments within 'inner Auckland', New Zealand.


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